Know Your British Lizards!

 

Britain doesn't have many lizards, so surely it's not difficult to work out which species is which? Wrong! I sometimes get confused, and I know that I'm not alone. It doesn't help that lizards don't always hang around to give you a good view. Too often, you only see a flash of movement or catch a glimpse of a tail vanishing at speed under a rock or into a bush. 

Anyway, as a budding reptile surveyor  I've been trying to learn the key identification features that separate Britain's lizards. In doing so I have relied heavily on the two field guides mentioned at the end of this post, strongly supported by guidance and training from experts including Sue Searle, Howard Inns and Rick Sharp. My notes have somehow ended up as this blog post, which I hope that you find useful too. The photos are all my own.

It's also worth knowing that Amphibian and Reptile Conservation, who do much to conserve and promote Britain's reptiles, have prepared a useful (and free) online reptile identification guide which covers snakes as well as lizards. It can be downloaded from their website (link here). 

I'm focusing here on four species: three lizards that look like lizards - Common (or Viviparous) Lizard Zootoca vivipara (pictured at the top of this blog post), Sand Lizard Lacerta agilis and the non-native Wall Lizard Podarcis muralis - as well as the legless Slow Worm Anguis fragilis. I've included Wall Lizards because they have become well-established in a number of mainly coastal sites in the south of England - many of which are in Dorset where I'm based - see my blog post here.

I've concentrated on features that can be distinguished by the field observer, ideally with a photograph, rather than anatomical details that require an 'in-hand' examination such as femoral pores and supraciliary granules. For most of us this is simply impractical, and for Sand Lizards it would be illegal without a licence, as that species is protected in the UK - so don't even think about picking one up! I'm sure that most of us would rather avoid disturbing these lovely creatures in any event.   

The Slow Worm is probably the most common of all our reptiles, being found right across mainland Britain. Having no legs, it can be clearly distinguished from our other lizards, looking in the first instance more like a snake. But on closer inspection you'll see that they have a less slender and more chunky profile than our three native snakes, as well as a distinctly Common Lizard-like head. 

Slow Worms are the most likely lizards to turn up in a back garden. If they arrive in yours then count your blessings and try to maintain a patch of undisturbed long grass and a few bushes for them. Compost heaps go down particularly well.

Slow Worm (male) - Dorset

The photo above shows a male Slow Worm. These are usually a uniform light brown colour sometimes dotted with startling blue spots. In contrast, the females tend to have darker sides and/or a dark stripe along the back (the dorsal or vertebral stripe) - see below. 

Slow Worm (female) - Dorset

The dark sides and dorsal stripe are also characteristic of juvenile Slow Worms. However, these will (unsurprisingly!) be much smaller than adults with brighter and more clearly defined markings. The dorsal stripe on juveniles often ends in a dot next to the head, as in the example below.

Slow Worm (juvenile) - Dorset

Right, onto lizards with legs. These are more tricky, but at least they do look like lizards.

First, the magnificent Sand Lizard. 

Sand Lizard male - RSPB Arne, Dorset

Sand Lizards are the most distinctive of Britain's legged lizards. (I did a blog about them last year, which you can find here). The key distinguishing features are set out below, but please be aware that Sand Lizards are a strictly protected species, so keep your distance and avoid disturbing them or their habitat.

• Sand Lizards are larger than either Common or Wall Lizards, with a total length of up to 25cm rather than 22cm (Wall Lizard) or 20cm (Common Lizard). Not that this helps with smaller individuals!
• Sand Lizards usually have two white or cream-coloured streaks down the back (dorsal streaks) - see the photo below.
• The spots on male, female and juvenile Sand Lizards are usually ocellated, meaning that they have a lighter ("eye-spot") in the middle. This is a key feature that is not present on Wall Lizards, although you need to look carefully at the spotting on female Common Lizards especially when they are flattening themselves while basking in the sun.
• As my photos show, male Sand Lizards usually have striking green flanks. However, females are brown all over, dotted with ocellated spots (no photos - apologies). But beware! Male Wall Lizards can also show green, which gets brighter during the breeding season (see the photo later in this blog post) and you can occasionally see green Common Lizards. But in both cases, any green on Common and Wall Lizards extends across the back, while on male Sand Lizards it is restricted to the sides. 
• Sand Lizards are generally more heavily built, or "chunky", than Common or Wall Lizards.
• The final point to bear in mind about Sand Lizards is that in Britain they have a limited distribution, being confined generally to heathland in Dorset, Hampshire and Surrey along with sand dunes near Southport, Merseyside. They have been more recently introduced to sites in Devon, Cornwall, Berkshire, North Wales and Kent (possibly more). However, I'm not aware of any British locations where Sand Lizards co-exist with Wall Lizards.

Sand Lizard (male) - RSPB Arne, Dorset

Next, Common Lizards. These are also known as Viviparous Lizards, as they give birth to live young rather than the egg-laying Sand and Wall Lizards, but I'm using Common Lizard in this blog for simplicity. Like Slow Worms, the range of Common Lizards extends in theory (and on the distribution maps of many field guides) across the whole of mainland Britain. But in practice they are more scarce, and may be absent from large areas of intensively farmland or built development. Generally, they favour undisturbed and open landscapes such as heaths or downland; in the former setting, their range overlaps with that of Sand Lizards although Common Lizards tend to prefer damper and grassier places while Sand Lizards are happier in drier areas dominated by heather and gorse.  

Common Lizard - Higher Hyde Heath, Dorset - showing re-grown tail

Distinguishing male and female Common Lizards is far less easy than for Sand Lizards. Males are generally more speckled, while females tend to look more stripey. I think that the photo above is probably a male, given the flecked pattern on its back, but the obvious light-coloured stripes give me some pause for thought. Nobody said it would be straightforward! (If the belly is visible, which it isn't in this image, then things get easier: males have a yellow-orange underside, while females are a plainer beige colour below.)

So, what are the key identification features that distinguish Common Lizards from Sand and Wall Lizards? As noted above, both Sand and Wall Lizards have very restricted distributions in Britain. If you are not on lowland heath or coastal dunes then you are highly unlikely to be looking at a Sand Lizard, while Wall Lizards tend not to stray far from their known colonies, which are mostly in Southern England (see here for more details). However, if you are in an area of possible confusion then the following may help:

• Compared to Sand Lizards:
• Common Lizards generally do not show any green colour, but if green is present then it will be right across the back and not confined to the sides. It will also usually be less vivid than the green of a male Sand Lizard.
• Any spots on Common Lizards will usually not be ocellated, so will appear as white flecks rather than dark spots with a central white "eye". 
• Common Lizards are smaller and more slender, with much less bulky heads than Sand Lizards (see photos below).

Common Lizard - head 

Sand Lizard - head

Wall Lizard - head

• Compared to Wall Lizards:
• Common Lizards tend to be slightly smaller than Wall Lizards, although this is not always obvious and you very rarely (i.e. never!) see both species side-by-side to compare.
• The markings on Common Lizards are generally either speckles (including patches of white) on the males or light-coloured stripes on the females, while Wall Lizards usually have more mottled markings (see photo below).
• Common Lizards have a blunter snout than the more pointed snout of Wall Lizards. This is just about apparent in the respective head photos above, but in the field I find that I need either a very  good look at the lizard or a decent photograph.
• Although by no means definitive, Common Lizards tend to be seen in flatter, grassy areas, while Wall Lizards are usually not far away from a vertical rocky habitat: they are well-named. Even though the Wall Lizard photographed below was basking on leaf litter, it was less than a metre from a large south-facing stone wall.

Wall Lizard showing mottled pattern - Abbotsbury, Dorset

Finally, this brings us to Wall Lizards. Strictly these are called Common Wall Lizards, as there are a wide variety of wall lizard species across Europe (see Speybroeck et al., 2016), but I've deleted the "Common" in this blog for reasons of clarity, given the risk of confusion with Common Lizards.

Wall Lizard male with bright colouration - Abbotsbury, Dorset

The main identification features that distinguish Wall Lizards from Sand and Common Lizards have already been described above, so there's no need to restate them again in detail. The important thing to remember is that the colouration of Wall Lizards is very variable, and males of the populations of southern England can have either green or brown backs depending upon where the original introduction was sourced (generally green from Italy and brown from France). Colour alone is generally not a reliable way of separating Wall Lizards from Common Lizards, although a useful tip is that some male Wall Lizards show a blue patch on the side of the belly - see the example below from Portland, Dorset. As far as I'm aware this is not a feature found in Common Lizards.

Wall Lizard male with brown back and blue sides to belly - Portland, Dorset

Anyway, I hope that this is helpful - do let me know if I've made any errors or if anything isn't clear. I intend to update this post as I get more field experience with these species.

Postscript: For the sake of completeness, I should add that there is a further lizard species on British soil - the (Western) Green Lizard Lacerta bilineata, which as well as being a native of Jersey, an island that also hosts native Wall Lizards but no Common Lizards, has a longstanding introduced population in Bournemouth of all places. Western Green Lizards are large (up to double the size of a Sand Lizard) and truly spectacular. I have yet to get a decent photograph of one, but in compensation here's the very similar Eastern Green Lizard L. viridis photographed in northern Greece. Enjoy!

(Eastern) Green Lizard - Lake Kerkini, Greeve

References

Inns, H. (2009). Britain's Reptiles and Amphibians Wildguides

Speybroeck, J. et al. (2016) Field Guide to the Amphibians & Reptiles of Europe (British Wildlife Field Guides) London: Bloomsbury.

 

Wall Lizards in Dorset

 

Common Wall Lizard - Abbotsbury Subtropical Gardens, Dorset

Most field guides will tell you that Britain has six native reptile species - Common (or Viviparous) Lizard, Sand Lizard, Slow Worm, Adder, Grass and Smooth Snakes. (See my blog about Sand Lizards in Dorset here.) However, Dorset is home to another reptile - the Wall Lizard - and in some coastal corners of the county it's a lot more common than any of the native 'big six'.

One of these corners is the Isle of Portland (not strictly an island, but that's another story) where Wall Lizards are easily encountered. On a recent walk down its eastern side (early May 2025) we saw nine Wall Lizards and no native reptiles. Our sightings were all in an area around Cheyne Weares, specifically on the coast path that winds through the undercliff south of Church Ope Cove and on the wall that separates the main road from Coombefield Quarry. It was mid-morning after a foggy start, ideal conditions to see reptiles basking on sheltered and sunny rocks. The two pictured below allowed me to get close enough to grab some images with my phone. Note the blue patch on the side of the belly on the second lizard, likely indicating a male. 

 

Common Wall Lizards - Portland, Dorset May 2025 (iPhone images)

Strictly, these are Common Wall Lizards Podarcis muralis, which are found across southern Europe from France and northern Spain to western Turkey. Within their native range they are able to tolerate human-influenced environments, and are as familiar on dry stone walls and farm buildings as they are in forests and on mountain scree. The first time that I came across them was in a hamlet in the Cévennes in south central France where they were active and engaging residents of our small rural gîte.

But what are they doing in Dorset? The Surrey Amphibian and Reptile Group (SARG)'s Wall Lizard Project (see reference at the end of this blog post) provides some of the answers, even though the website's maps weren't fully functional when I recently accessed it. The project has identified 14 extant Wall Lizard colonies within Dorset, all in coastal or near-coastal locations. The two that I am most familiar with are at Cheyne Weares on Portland, see above, and in Abbotsbury Sub-tropical Gardens further to the west towards Bridport (link here), which are worth a visit even if lizard-spotting isn't on your agenda. The SARG project mentions a second site on Portland at the West Weares, which includes Tout Quarry, but I myself have never seen a Wall Lizard on that side of the island. We had another look on our last visit with no success, although it was later in the day and temperatures had risen markedly.  

According to the SARG project, the Abbotsbury colony is long established, possibly dating from as early as the 1890s, while both Portland colonies are more recent, arising from captive stock released by a private breeder in the 1990s. It should be noted that this is illegal: the release of any non-resident (or non-regularly visiting) wild animal is prohibited by the Wildlife and Countryside Act 1981. Not that this seems to stop people, as shown by the UK's current wave of mysterious beaver arrivals.

Such laws are eminently sensible: much of the world has experienced the downside of non-native introductions, from Cane Toads in Australia to Japanese Knotweed in the UK. While greater species diversity could be welcomed given Britain's impoverished fauna, which has resulted both from its island nature and subsequent extinctions at the hands of its human occupants, any re-introductions should always be done with an understanding of the likely costs and benefits.  

Common Wall Lizard - Abbotsbury

So what are the costs and benefits of having Wall Lizards in Dorset? Obviously they are already here, and they look very much at home. Given that their native range extends up to the French coast across the English Channel they would probably have colonised Britain naturally if they had arrived before the land bridge was lost after the last Ice Age. Climate change means that conditions in Dorset are likely to become more favourable to their survival. 

While this suggests that we probably shouldn't be too concerned about the presence of Wall Lizards, recent research (see Williams, 2019) indicates that there is clear potential for them to compete for resources with native reptiles, specifically Viviparous Lizards. In the jargon, this is called "niche overlap". The extent to which competition could become a conservation problem for the native species is uncertain; Wall and Viviparous Lizards appear to coexist successfully over much of northern France, although generally the two species have distinctly separate ranges - Viviparous Lizards in northern Europe and Wall Lizards further south, although Wall Lizards are themselves replaced by a suite of related species over much of Spain and Portugal.

To date, while many of Dorset's Wall Lizard colonies seem to be in good health, there is little evidence of them having expanded into the wider countryside. If they stay contained then there is less likelihood of harmful conflicts with our native reptiles. The SARG project suggests that Portland has historically been poor in terms of reptile numbers, presumably because of its relative isolation from the rest of Dorset, so the presence of Wall Lizards may be less of a concern on the island.

On the other hand, although Viviparous Lizards are classed as 'least concern' in conservation terms by the International Union for the Conservation of Nature (IUCN) "red list", their numbers are reducing in certain areas of Britain (Foster et al, 2021) - albeit not severely enough to affect its overall conservation status. Habitat loss and reduction in habitat quality are the main factors affecting local populations, although a reduction in prey density as a result of declining insect numbers (see my blog about that here) may be an additional factor and competition with non-native introductions like Wall Lizards cannot be ruled out. One to watch for the future. 

Common Wall Lizard - Abbotsbury Subtropical Gardens

In the meantime, let's just enjoy Wall Lizards for what they are, characterful and engaging reptiles that can put on a bit of a show for residents and visitors alike. Anything that encourages folk to notice and enjoy wild nature, even if its been given a bit of a helping hand, can only be a good thing.

References

Beebee, T. & Griffith, R. (2000). Amphibians and Reptiles (New Naturalist Series) London: HarperCollins.

Foster, J., Driver, D., Ward, R. & Wilkinson, J. (2021). IUCN Red List assessment of amphibians and reptiles at Great Britain and country scale. Report to Natural England. ARC report. ARC, Bournemouth.

Inns, H. (2009). Britain's Reptiles and Amphibians Wildguides

Langham, S. (2025) The Wall Lizard Project Surrey Amphibian and Reptile Group; 2025-05-03. 2025-05-03 <http://surrey-arg.org.uk/SARGWEB.php?app=PmSitePicker>. link

Speybroeck, J. et al. (2016) Field Guide to the Amphibians & Reptiles of Europe (British Wildlife Field Guides) London: Bloomsbury.

Williams, R.J. (2019). The Invasion Ecology of Common Wall Lizard (Podarcis muralis): Population Dynamics, Interactions and Adaptations (Doctoral dissertation, University of Leeds).

Capuchins and Squirrel Monkeys: Primates of Costa Rica (part 2)

 

White-throated Capuchin Monkey

My last blog looked at the largest of Costa Rica's four primate species: the Mantled Howler and Central American Spider Monkey. Now it's the turn of their two smaller relatives.

Capuchin Monkeys are a common sight throughout the Neotropics. Unlike the two species covered in my last blog, which both feed mainly in the forest canopy, Capuchins will forage on the ground as well as in the treetops. Their diet is wide-ranging, both plant-based (fruits, seeds, flowers and buds) and carnivorous (insects, as well as smaller birds and mammals). The name relates to a supposed likeness to brown-robed monks, a likeness that has also (bizarrely) named the cappucino coffee, although I can't see it myself. 

Their sole appearance on our trip was unexpected. All four of Costa Rica's primates prefer to live in forests, ideally primary rainforest. So we weren't expecting to see any in the lowlands of the south-west, where the forests have been largely cleared and farming is the dominant land use.

Wetlands near Cuidad Neilly - not an obvious monkey habitat

We were exploring the extensive wetlands near Cuidad Neilly, near to Costa Rica's border with Panama. Much of the land had been flooded for rice cultivation and the birding was simply sensational. This is a land of waterfowl, waders and herons.

Bare-faced Tiger-Heron near Cuidad Neilly

We found ourselves walking along a track bordering the Rio Corredor, which has been forced into an arrow-straight corridor through the wetlands. The track was flanked by narrow strips of trees and shrubs, and it was there that the Capuchins announced their presence by the sudden wave of activity, chattering and branch-breaking that accompanies a troop of monkeys on the move.

Riverside trees and shrubs - where we discovered the Capuchins

It was difficult to get a good view, as they were mobile and largely concealed by leaves and branches. Every now and again an inquisitive face would pop up in a gap through the vegetation, and it was a challenge to fire off a few photographs before its owner disappeared again.

Capuchin in pensive mood

Like Costa Rica's other primates Capuchin Monkeys have been under the scrutiny of taxonomists, which means that you will find different species names for them in different publications. I favour the IUCN Red List (website) which now calls them the Panamanian White-throated Capuchin Cebus imitator. Why Panamanian and not Costa Rican I do not know: they are found in both countries, as well as parts of Nicaragua and Honduras, but they appear to be more widely spread across Costa Rica than anywhere else. The species has been split from the (similar) Colombian White-throated Capuchin Monkeys found in eastern Panama and parts of Colombia and Ecuador. Sadly, both species are considered at risk, being classed as "vulnerable" by the IUCN due to concerns of forest loss as well as hunting for bushmeat and the pet trade. Their tendency to raid crops doesn't make them hugely popular with farmers, either. 

Capuchin Monkey peering from the forest gloom.

Unfortunately things are even worse for the fourth and final Costa Rican primate, the beautiful Squirrel Monkey - or, to be exact, the Black-crowned Central American Squirrel Monkey Saimiri oerstedii. (Taxonomists don't appear to give much thought to producing snappy or memorable common species names, do they?) This is the rarest of Costa Rica's monkeys, and many visitors never get to see one. However, we were lucky to have brief views of a small group of at least five individuals moving high through the forest canopy in the Piedras Blancas National Park, a marvellous tract of lowland rainforest in the south-west of the country near the town of Golfito. 

Black-crowned Central American Squirrel Monkey - Piedras Blancas National Park, Costa Rica

These are really neat little monkeys, with a distinctive black cap and - unusually for Neotropical primates - a non-prehensile tail. Not that this seemed to impede their movement through the canopy; our five were walking confidently along horizontal vines and creepers before we lost sight of them.

These Squirrel Monkeys occupy a very restricted geographical range (see the map here) being limited to the Pacific coasts of Costa Rica and western Panama. They are well-separated from the Squirrel Monkeys of South America, leading to speculation that they were brought to Central America by man - unlike the other three species described in my two blog posts. However, there are clear differences from the South American species, including a more orange-coloured back (which is not shown well in my photograph which was taken after a short and heavy burst of rain), which suggests that they have been established as a distinct population for enough time to evolve into a separate species.

Animals with limited geographical ranges are often at a greater risk of extinction because they are reliant upon a smaller number of protected areas (among other reasons). That is certainly the case with these Central American Squirrel Monkeys, which are classed as 'endangered' by the IUCN. It doesn't help that they are confined to the lowlands, so cannot benefit from the more extensive range of national parks and reserves along Cosat Rica's central mountain chain. You won't see any up at Monteverde, for example. Continued safeguarding of places like Piedras Blancas and Corcorvado National Parks is essential for their survival. As in my previous blog, I am waving the flag to increase awareness of conservation organisations that working to protect such habitats, such as the World Land Trust. If you are able to lend support then please do.

Sources

Emmons, L. H. (1997) Neotropical Rainforest Mammals: A Field Guide (2nd ed) Chicago: Chicago UP

Henderson, C.L. (2010) Mammals, Amphibians and Reptiles of Costa Rica. Austin: University of Texas Press.

Solano-Rojas, D. 2021. Saimiri oerstedii. The IUCN Red List of Threatened Species 2021: e.T19836A17940807. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T19836A17940807.en. Accessed on 17 February 2025.

Williams-Guillén, K., Rosales-Meda, M., Méndez-Carvajal, P.G., Solano-Rojas, D., Urbani, B. & Lynch Alfaro, J.W. 2021. Cebus imitator (amended version of 2020 assessment). The IUCN Red List of Threatened Species 2021: e.T81265980A191708420. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T81265980A191708420.en. Accessed on 17 February 2025.

Howlers and Spiders: Primates of Costa Rica (part 1)

 

It is just after dawn on a road through the dry forest that flanks the Pacific Ocean. Breakfast has been postponed so that we can catch the morning's first rush of bird activity. A White-throated Magpie Jay flaunts its tasselled crest, while a startling yellow Prothonotary Warbler shimmers through the foliage. Attuned to such small movements, it comes as a surprise when a large black object crashes through the bushes and pauses in a fork of branches to give you a hard stare. This is a Mantled Howler Monkey Alouatta palliata, the most conspicuous of Costa Rica's four primate species. 

Howlers can turn up in forests all over Costa Rica, from the coast to mid-elevation rainforests (around 2,000 metres up). We first heard them at Pocosol Biological Station, a rainforest research facility at the end of a long and bumpy track through the foothills, where their soundtrack of hooting calls echoed over the forest canopy as dawn was breaking. But they didn't show themselves at Pocosol: our first distant sighting was of several black specks in trees across the Rio Frio down on the Nicaraguan border at Los Chiles a couple of days later, where the now-familiar Howler chorus accompanied the evening bustle of comings and goings on the town's busy waterfront.

After that, Howlers seemed to appear in every large forest that we visited. At Tirimbina Rainforest Reserve, in the foothills on the Caribbean side of Costa Rica's central mountain chain, a troop of Howlers passed through the canopy right above us, sending down one individual for a closer look (below). They were interested in us human visitors, without wanting to get too close; this may be a response to what they see as a possible predator, or it might be just exploiting the potential for a food handout. Certainly, Howlers are tolerant of some degree of  human activity and can occupy more disturbed secondary forest habitats: we saw one near to our hotel entrance at Quinta de Sarapiqui for example.

Mantled Howler Monkey - Tirimbina, Costa Rica

Howler Monkeys are found across the tropical forests of Central and South America where their diet comprises mostly young leaves of a variety of rainforst trees. This isn't the most nutritious of foods, but at least there's plenty of it, although the Howlers need to be careful to avoid eating leaves from the more toxic tree species. This leads to an ongoing evolutionary 'arms race' between hungry monkeys and ever-more sophisticated plant defence mechanisms.    

From the six Howler Monkey species listed by Louise Emmons in 1997, we have jumped to 15 species that are now recognised by world conservation body the IUCN. Several of these newly defined species have very limited ranges, but Mantled Howlers can be found across much of tropical Central America and down the Pacific coast to southern Ecuador. Despite this large range, they are a conservation concern (classed as "vulnerable") as numbers have decreased by at least 30% over 30 years. Threats include hunting and habitat loss.

While Mantled Howler Monkeys may be the heaviest of Costa Rica's four primate species, they are not necessarily the biggest. What Central American Spider Monkeys Ateles geoffroyi (below) lack in bulk, they make up for in reach. These lanky, long-limbed canopy dwellers are well-named.

Central American Spider Monkey - Tirimbina, Costa Rica

Tirimbina Rainforest Reserve (website), which should be on the itinerary of every naturalist visiting Costa Rica, provided our only encounter with this elusive species. Unlike the Howlers, they showed no interest in coming close, and we had to be content with glimpses through the thick forest foliage. The photograph above shows the light-coloured facial markings that distinguish them from the mostly-black Howlers, while the poor image below gives a better impression of their spider-like profile. Although most New World monkeys have prehensile tails that can grip round branches, Spider Monkeys seem particularly adept at using it as a fifth limb, making short work of the complex job of navigating through the tangled forest canopy. They moved with an effortless style.

Spider Monkey silhouette - Tirimbina, Costa Rica

Unlike the leaf-eating Howlers, Spider Monkeys seek more nutritious forest foods such as fruits, seeds, flowers and even some small animals. These can be scarce resources, and as a result Spider Monkeys need to range across a large area of forest. This means that their territories are bigger, sometimes over 100 hectares, than those of the more sedentary Howlers which can manage in under 60 hectares. Mind you, Spider Monkeys tend to move around in bigger numbers than Mantled Howlers: groups can number up to 50 individuals, compared with 10-20 Howlers, although the our Spider Monkeys at Tirimbina were far fewer in number.   

Sadly, the conservation picture for Central American Spider Monkeys is even worse than for the Mantled Howlers. The species has a somewhat limited range, being confined solely to Central America, following a taxonomic split that has separated them from a population in Colombia and western Ecuador now called Brown-headed Spider Monkeys Ateles fusciceps. These are also endangered. Central American Spider Monkeys have suffered an even greater population loss than the Howlers: a 50% reduction over 45 years. Habitat destruction is the main culprit, although hunting for bushmeat and the pet trade is also a concern.

While Costa Rica can boast an excellent network of protected forests, this doesn't mnean that the future of species like these two primates is secure. Conservation organisations working to safeguard such habitats, such as the World Land Trust which I have been supporting for over 20 years (and which operates on Costa Rica among many other locations), need all of the help that they can get. 

Right - two primates down, and two to go. Watch this space.

Mantled Howler - Quinta de Sarapiqui, Costa Rica

Sources

Cortes-Ortíz, L., Rosales-Meda, M., Williams-Guillén, K., Solano-Rojas, D., Méndez-Carvajal, P.G., de la Torre, S., Moscoso, P., Rodríguez, V., Palacios, E., Canales-Espinosa, D., Link, A., Guzman-Caro, D. & Cornejo, F.M. 2021. Alouatta palliata (amended version of 2020 assessment). The IUCN Red List of Threatened Species 2021: e.T39960A190425583. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T39960A190425583.en. Accessed on 02 February 2025.

Cortes-Ortíz, L., Solano-Rojas, D., Rosales-Meda, M., Williams-Guillén, K., Méndez-Carvajal, P.G., Marsh, L.K., Canales-Espinosa, D. & Mittermeier, R.A. 2021. Ateles geoffroyi (amended version of 2020 assessment). The IUCN Red List of Threatened Species 2021: e.T2279A191688782. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T2279A191688782.en. Accessed on 02 February 2025.

Emmons, L. H. (1997) Neotropical Rainforest Mammals: A Field Guide (2nd ed) Chicago: Chicago UP

Henderson, C.L. (2010) Mammals, Amphibians and Reptiles of Costa Rica. Austin: University of Texas Press.

Snow Bunting - Poole Harbour

Snow Bunting - Hamworthy, Dorset 14.1.25

If like me you play the game of trying to see as many birds as possible in a year, then January is an exciting time. After a good birding year (200 UK species plus a couple of overseas trips), I had made a loose New Year's resolution to take things easier in 2025. So when I returned from celebrating Hogmanay with friends in Scotland and discovered that a Snow Bunting had been reported at Hamworthy Park in Poole I didn't immediately take the bait.

However, the bird, which had first been sighted on 30 December last year, showed no desire to move away, and so this morning I finally cracked and headed over for a look.

At first sight, Hamworthy Park looks like an unlikely place for a Snow Bunting to decide to spend the winter months. Although sited on the harbour edge, where the waterside walkway was being enjoyed by a lot of dog walkers this morning, the park's close mown grass flanked by a line of beach huts hardly adds up to a slice of prime habitat. And while Poole Harbour has a history of hosting the occasional Snow Bunting, they generally favour its wilder corners, such as the one at Redhorn Quay on Studland in November 2021 (below).

Snow Bunting (2021) on the wilder side of Poole Harbour - Studland, Dorset

The 2021 Studland Snow Bunting was a flighty thing, rarely settling in one place and easily spooked by passing people. I was one of two or three birders watching it that day, and we took care to keep our distance. Not so at Hamworthy Park this morning. This Snow Bunting was perched on a noticeboard just metres away from a small group of admiring locals, whose dogs ran cheerfully around chasing balls and paying the bird no attention whatsoever. The Snow Bunting was so close to these people that I'd almost walked past before I realised what they were looking at. I had mistakenly assumed that the bird would be avoiding passers-by. In contrast, it seemed to almost be enjoying the attention. My 400 lens felt like an overkill - I could probably have used my phone camera to similar effect.  

Snow Bunting - Hamworthy 14.1.25

I had a chat with the people watching the bird. None were birders, and all seemed very pleased that it had chosen their park to spend the winter in. They were especially interested in where it might have come from. You can't say for sure of course, but I did mention that wintering Snow Buntings were regularly seen on the UK's coasts, albeit more commonly on the east coasts of Scotland and England, and that the species did breed in small numbers in the Scottish Highlands - where I've seen small flocks on several Munros (Scottish mountains over 3,000 feet). However, most of the UK's Snow Bunting winter visitors are likely to be migrants from the continent, breeding in northern Scandinavia and Arctic Russia.

Doing some subsequent research, I see that while large flocks of wintering Snow Buntings have been reported on eastern English coasts in the past, there are large variations in numbers depending on weather variations in the near continent (Brown & Grice, 2005). In Dorset, where the species is described as a scarce passage migrant and rare winter visitor, recent records have been single individuals onl,y with (for example) fewer than 10 birds recorded on passage in 2023 (Dorset Bird Club, 2024). This accords with my experience: I've never seen more than a one bird at any one time on the coasts of either England or Scotland.

The Hamworthy Snow Bunting fits in with this pattern, although its presence in a single location for over two weeks is unusual. One of the locals that I spoke to suggested that food may be being put out for it, which would perhaps explain why it seemed so relaxed in the company of people. However, I saw no evidence of seeds or other bird food lying around. 

I left feeling both positive about the obviously warm welcome that the Snow Bunting has received in Hamworthy and apprehensive about its future in a location with so little natural cover. It will be interesting to see whether the bird stays on here - and if so, for how long. 

But in the meantime, I'm enjoying reflecting on these fantastic views of such an attractive winter visitor.

Snow Bunting - Hamworthy, Dorset 14.1.25

References

 

Brown, A. & Grice, P. (2005) Birds in England. London: T & AD Poyser

Dorset Biird Club (2024) Dorset Bird Report 2023.

  

     

Top Ten Birds of Costa Rica: #1 Scarlet Macaw

The Scarlet Macaw Ara macao was an easy choice to crown my Top Ten Birds of Costa Rica. Large and extravagently coloured, their appearance on first sight is so striking as to challenge your perceptions of a wild bird - a real wake-up moment. Perhaps it's because we are so used to seeing Scarlet Macaws in captivity, or perched on some fictional pirate's shoulder, that it comes as a jolt to see them to see them flying around and interacting with each other like, well, any other bird. And let me say at the outset that they are neither bashful nor retiring when doing that. If they are in the vicinity then you will know about it.

Although widely distributed across the Amazon basin, Venezuela and Colombia, Scarlet Macaws have a more patchy presence in Central America. They are classed as being of 'least concern' in global conservation terms, but their numbers are declining nevertheless and the IUCN suggests that they are possibly extinct within areas of their former range in Mexico, Guatemala, Nicaraugua and Honduras. The last of these is potentially embarrassing, as they are the national bird. Capture for the pet trade remains a serious threat, as well as the more common problems of habitat loss and degradation. Within Costa Rica, my well-thumbed bird guide (Garrigues & Dean) highlights only three small areas of the country where they are likely to be found, all on the Pacific coast.

This was a worry. If the range of the species is so restricted, would we manage to track them down? But our guide Pat O'Donnell was quietly confident. And with good reason: they proved almost ridiculously easy to find. As I later discovered, Costa Rica is one of the best places in the Neotropics for Scarlet Macaw sightings - as the map of global records highlights (see GBIF).

Scarlet Macaw habitat - Beach Almond trees at Tarcoles

The small seaside village of Tarcoles lies almost mid-way along the main road down Costa Rica's Pacific coast. The nearby Tarcoles River signals the boundary between two of the country's major habitat zones, the dry north Pacific lowlands and the more humid lands to the south. The road bridge over the river is also the best place in the country to spot American Crocodiles, but that's one for another blog post. Driving south across the river, Pat turned off the main road and headed for the beach (Playa de Tarcoles). We pulled up on a rough gravelled parking area (photo above) flanked by a grove of Beach Almonds Terminalia catappa. This tree is a non-native species from India. It might not be an actual almond, but it is hugely favoured by Scarlet Macaws.  

We could hear their raucous calls as soon as we stepped out of the vehicle. A couple of birds flew north in a flash of colour, but the sounds were still coming so we set off to investigate. And there on the outside of the deep green foliage of a nearby tree I had my first proper sighting:

First sighting of a Scarlet Macaw - Tarcoles, Costa Rica

For such a colourful bird, Scarlet Macaws can blend into the canopy of a Beach Almond tree surprisingly well. There turned out to be two birds in this tree, and they both kept moving. Getting a good view of them both needed some patience ...

Scarlet Macaws blending in

... which finally paid off:

The two birds appeared to be a pair. At first sight, there is little obvious difference between male and female Scarlet Macaws, but these two stuck close together, paying each other plenty of attention in between detours to seek out the tree's fruits. There was much mutual preening - and more. It was difficult to tell whether they were trying to mate or having a fight - but then that's long standing relationships for you, I guess.

Scarlet Macaws getting friendly

I found myself wondering why Scarlet Macaws are so insanely colourful; even within the notably gaudy parrot family the colour mix and brilliance of their plumage looks excessive. There are some useful pointers in a 2020 paper by Luisana Carballo and colleagues (see references below: link to paper here). This suggests that larger parrots living in warmer environments are the most colourful (Scarlet Macaws certainly tick both of those boxes), and that mutual mate choice and social selection may be more powerful evolutionary factors than maintaining crypsis (i.e. camouflage). Getting the right mate is particularly important in long-lived species that sustain a pair bond over many years, especially when resources are scarce, such as the larger cavities that these big birds need to nest in. Bright colours may be seen to signal a stronger and fitter individual, and as both males and females are both being choosy, both sexes are therefore vibrantly coloured. Or that's the theory, at any rate.

But it sounds like it's on the right lines. As shown in some of my photos, just because Scarlet Macaws are brightly coloured, it doesn't follow that they are always conspicuous. The red, yellow and blue combination can act to break up the macaw's overall shape (an idea called "disruptive colouration"), possibly confusing potential predators when several are in flight together. And perhaps counter-intuitively this colour pattern can also make the birds harder to make out within the canopy of an evergreen forest tree, which is a mix of light, shade and various colours as these photos show.

And as always, the science merely adds to the wonder of meeting one of the world's top birds - a true wildlife highlight on which to end this short blog series. (Although there will be more from Costa Rica to come, I think.)

References

BirdLife International (2022). Ara macao. The IUCN Red List of Threatened Species 2022: e.T22685563A163778999. [online] https://dx.doi.org/10.2305/IUCN.UK.2022-2.RLTS.T22685563A163778999.en. 

Carballo, L., Delhey, K., Valcu, M. and Kempenaers, B. (2020). Body size and climate as predictors of plumage colouration and sexual dichromatism in parrots. Journal of Evolutionary Biology, 33(11), pp.1543-1557.

Top Ten Birds of Costa Rica: #2 Snowcap

With its rich burgundy plumage topped by a shocking white crown, the Snowcap male is one of the most instantly recognisable hummingbirds of the Neotropics. So recognisable, in fact, that our guide Pat O'Donnell's description of himself when we first met at San Jose airport was: "look for the guy with the Snowcap t-shirt". We found him with no difficulty. 

Even within such a showy family as the hummingbirds, the Snowcap Microchera albocoronata stands out. No other hummer has the combination of a white cap and a body colour that varies from gold to bronze to burgundy to something best described as "beetroot" depending on how the light is shining on it. This is all down to the iridescent plumage of course, which itself is a function of the shape and position of pigment cells within the detailed stucture of the feathers. 

The result is - literally - breathtaking, producing in my case an involuntary gasp of excitement. We were returning from a morning's walk along the trails at Pocosol Biological Station, which had produced such delights as a Checker-throated Antwren and a close view of a Bicolored Antbird, and had just passed the accommodation building when Pat gestured urgently towards a small line of Porterweed bushes. There on the top, positively glistening in the morning sunshine, was my first Snowcap. And it was just as well that the bird is so easy to identify. Within a couple of seconds it had gone, chased away by the jealous and attentive Rufous-tailed Hummingbird that had laid claim to this precious source of nectar. Rufous-tailed hummers are bullies! 

Unfortunately, the sighting had been so brief that my birding companion Richard missed it. To make matters worse, the Snowcap failed to reappear despite much searching. As all birders will know, it is intensely frustrating when you have failed to spot a bird that the others have seen, and when that bird is as sensational as a Snowcap it can all get a bit awkward. Despite putting a brave face on it, Richard was clearly put out. And while I could be excused a bit of smugness about being in the right place at the right time to "tick" the bird, what I really wanted was a more leisurely encounter, and, ideally, the opportunity to take a few photographs. But Pat decided to rise to the challenge. Finding another Snowcap became a top priority. 

The Snowcap is a hummingbird of the Caribbean slopes, ranging from Honduras in the north to Panama in the south. Like many Costa Rican species it is fussy about altitude. At around 720 metres above sea level, Pocosol is near the upper limit of its range, while it is rarely located below 300 metres, although this may be because so much of Costa Rica's lowland rainforest has been destroyed. Fortunately Pat has

literally written the book about where to watch birds in Costa Rica (link here), plus a useful blog about Costa Rica's best Snowcap-finding locations, so there could be few better people to steer us towards another one.

We succeeded a couple of days later at Centro Manu, a small family reserve lower down the Caribbean slope near Guapiles. It didn't look hopeful at first: we arrived in a torrential downpour and had to take shelter in reception building.

A wet afternoon at Centro Manu reserve

When the rain eased off, we decided to explore the reserve's small network of trails. These were very wet indeed - wellies were essential - and the forest was quiet. It seemed as if the arrival of rain in the later afternoon had prompted the local birdlife to simply shut up shop early for the night. All quite dispiriting. But on returning to reception, Pat was not so easily discouraged. "We'll just try the hummingbird garden while there's still light," he announced. The rain was still lightly spotting as we headed down the track, with - it must be said - low expectations.

Centro Manu - the hummingbird garden

The hummingbird garden (above) turned out to be a forest clearing containing a variety of small flowering shrubs. There didn't seem to be much activity, but we stationed ourselves at a suitable vantage-point and waited. And a hummingbird duly arrived, albeit a Rufous-tailed hummer which began to patrol the bushes in a typically defensive manner. This didn't bode well.

Rufous-tailed Hummingbird (from Pocosol) - a bit of a bully!

A couple of Montezuma's Oropendolas flapped overhead, and a Blue-chested Hummingbird made a brief appearance high in a nearby tree. This was good, but still not what we were really after.

And then, as in all of the best stories, we hit success. Weirdly, two male Snowcaps arrived almost simultaneously. One popped up high in the tree where we'd seen the Blue-chested; I called out "Snowcap!", while Richard shouted out the same thing. I assumed at first that we were both looking at the same bird, but then discovered that he had spotted one down on the Porterweed bushes. This second bird then perched obligingly on a bush at the opposite side of the clearing, and I was able to advance some distance towards it brandishing my Canon, which I'd put on a suitably high ISO setting. I didn't want to disturb the bird by getting too close, but even from where I was standing, its colours seemed to light up the gloomy evening.

Snowcap - Centro Manu reserve

Fittingly, it was the final bird of the day. We drove away from Centro Manu into the gathering darkness and made our way back to our base for the night at La Quinta de Sarapiqui. It was our last full day on Costa Rica's Caribbean slope, but further adventures awaited over the mountains on the Pacific coast.

And it is there that we shall meet my final choice for the Top Ten Birds of Costa Rica.