Saturday, January 23, 2010


The Island of Cozumel lies a mere 20km off the east coast of the Yucatan Peninsula and is only 45km by 15km in size. There are mangroves around the island's coast but the habitat is mostly "semi-humid" scrub, a fascinating tropical habitat type that does not grow particularly tall despite receiving reasonable quantities of water (rainfall). This habitat type is also found in the eastern Yucatan Peninsula.

The theory of island biogeography would predict that such an island have moderate biodiversity, limited by its small size but augmented by frequent arrivals from the mainland. Cozumel, however, is something of an enigma, since it has four endemic species and many distinctive endemic subspecies, perhaps surprising given its proximity to the mainland. The avifaunal mixture of Cozumel is also intriguing in that, although it shares some species with the mainland, there are a suite of species with a more Caribbean distribution, including for example the Western Spindalis that occurs on Cozumel but not on the mainland. Other bird like Yucatan (Yellow-lored) Parrots and White-crowned Pigeons don't mind making the crossing on a regular basis, apparently even twice daily in some seasons.

The four Cozumel endemic species include a hummingbird, a vireo, a thrasher and a wren. The hummer is the Cozumel Emerald, and what a beauty! Unfortunately, the long, deeply forked tail of the male doesn’t show very well in these photos... but you get the picture!

The Cozumel Vireo is very distinctive. This species spends most of their time skulking in the scrub and is not easy to see well.

I didn’t manage photos of the other two endemics – the skulking Cozumel Wren – basically a House Wren who probably took a liking to island living and decided they didn’t feel like traveling back north... well, at least migration suspension seems like the most plausible explanation (or maybe they discovered Tequila?). The fourth endemic, the Cozumel Thrasher, is now feared extinct. Apparently they were common until the hurricane in September 1988. Since then there have been very few sightings and it seems as though this species will not recover. Many other local breeding species took a hit in that hurricane but they have since recovered. Perhaps there was something unusual about the thrasher or perhaps there was a cocktail of factors with the hurricane being the last straw… we may never know!

Cozumel is also a good place to see some of the Yucatan Peninsula endemics. The Yucatan Vireo is an inch or more larger than the Cozumel Vireo, with a much larger bill and with a global range that is restricted to the eastern portion of the Yucatan Peninsula and islands, being found in the characteristic semi-humid tropical scrub habitat of the region and also in mangroves. As it turns out, Cozumel was the only place I saw Yucatan Vireo. Note how thick the supercilium is on this species.

Another Yucatan endemic that seems easier to see on Cozumel than elsewhere is the Yucatan Woodpecker. In most sites in the Yucatan the much larger Golden-fronted Woodpecker is easier to see than the endemic Yucatan Woodpecker, but on Cozumel the converse was true! Note the yellow nasal tuft on this species, one of the features that separate them from Golden-fronted Woodpecker. According to Howell the yellow should extend underneath the bill but that didn’t really seem to be the case with the Cozumel birds… anyone care to comment?

Yet another Yucatan endemic, the Black Catbird, skulks around in the shrub layer, sometimes coinciding with overwintering Gray Catbirds. Once again, this species was easier to see on Cozumel than most sites on the mainland.

Then there are those Cozumel endemic subspecies. On Cozumel endemic rufivertex subspecies of Yellow Warbler has a rufous crown, although in this photo the crown is not so easy to see. Migrant Yellow Warblers from the north also occur.

The caboti subspecies of Bananaquit is only found only Cozumel and a tiny portion of the northeasternmost corner of the Yucatan Peninsula. Their range is very disjunct from the mexicana subspecies which you can see in Belize, northeastern Guatemala, Chiapas and the southernmost parts of Veracruz and Oaxaca. The caboti subspecies of Bananaquit is larger and has a white throat as opposed to the grey throat of mexicana.

Cozumel’s endemic intermedia subspecies of Yellow-faced Grassquit has less black on the chest than mainland races.

Cozumel is the only place is Mexico to see the stunning Western Spindalis, formerly known as Stripe-headed Tanager. This species occurs on many Caribbean Islands and of course is a highly sought-after rarity in Florida. The first photos shows the vibrant colours of the male – a very cooperative little chap who popped up in front of me at eye level. The second photo shows the female enjoying a feast!

Other Cozumel residents with a Caribbean affiliation include the Caribbean Elaenia, found on offshore islands and the eastern most portion of the Yucatan peninsula. Like many flycatchers in this group this species is not easy to identify from other similar species; however, their bright orange lower mandible is a particularly noticable and recognizable feature.

The Caribbean Dove has a somewhat similar distribution to the Caribbean Elaenia; however, their range extend much further westward and also further south in the Caribbean Island chain. Not easy to tell from White-tipped Dove, but their grey, as opposed to vinaceous, crown is a good feature.

Cozumel also has its share of species with more widespread distributions. One of these is the handsome Mangrove Cuckoo. In my experience, Cozumel is the easiest place there is to see this skulker, which is notoriously difficult to find through much of their range. On Cozumel, this species is not confined to mangroves and I saw them in fruiting trees and also in semi-humid scrub.

The Bright-rumped Attila is a widespread flycatcher, ranging from Mexico to Brazil. This one popped up for me and gave good views for a minute or so. Note the hooked bill shape.

Tropical Mockingbird is also wide ranging, although, unlike most of the species covered in this post, they are easy to see anywhere in their range.

Cozumel also attracts its share of Nearctic breeding migrants, including a good selection of shorebirds like the beautiful Black-bellied Plover (American English) or Grey Plover (British English) or Silver Plover (me!).

Another migrant, a Sora, strolls around on some exposed mud. I don’t often see Sora this well up here on their breeding grounds!

And a Palm Warbler forages in the leaf litter… In a few short months, I will be surveying for this species and other boreal breeders as part of the Manitoba Breeding Bird Atlas… but they are content to stay on Cozumel for now!

Another familiar face – indeed a familiar masked face, Raccoons are resident on Cozumel. Like here in North America they are not shy about feeding on human garbage. On the other hand, there is no need to sleep away the winter months down on Cozumel!

More to come soon… but first, better go shovel that fresh snow!

Friday, January 15, 2010

Neotropical owls

Back recently from a trip to Mexico, Belize and Guatemala, which I will post about in more detail soon. Since I haven’t posted anything in nearly a month, I thought I would start quickly by sharing photos of some of the nightbirds from this trip. I put together and more comprehensive and organized series in due course.

We start with my lifer Crested Owl. This phenomenal looking creature is quite unique and placed in their own genus Lophostrix. Their voice is also rather unique, being exceptionally gruff, even for a large owl. I have wanted to see Crested Owl for a long time so on this trip, whenever I found myself in lowland rainforest, I spent my nights looking for this species. It wasn’t until near the end of my trip, at Palenque in Mexico (famous Mayan ruins) that I finally caught up with this enigmatic species. I had been birding in the ruins and then birded back down the entrance road very slowly after dark. After hearing a Crested Owl call it took nearly half an hour to track the caller down, so I was absolutely elated when I was able to maneuver into position to take this photo. Of course when I walked passed the military check point, they searched my persons and my backpack thoroughly (in case I had tried to smuggle out a relic) and not me I was not supposed to be on the road after dark (the people at the ticket counter had told me this was allowed). At that point, I didn’t mind the incursion – I already had my photos of Crested Owl.

Another highlight was this Bearded Screech-Owl at the Pronatura Reserve called Huitepec, near San Cristobal de las Casas in Chiapas, Mexico. It took three nights to find this species. On the first two, the wind picked up an hour before dusk and made listening for owls almost impossible. On the third night it looked like it would rain but instead the blanket of cloud and fog seemed to hold back the wind. As a result I got my lifer Bearded Screech-Owl and Unspotted Saw-whet Owl, although I didn’t manage a photo of the latter. The Bearded Screech-Owl, like many screech-owls in dichromatic, i.e. there are two colour morphs, red and grey. This bird is obviously a red morph individual. Notice also the long wings relative to the tail and the naked (unfeathered) toes characteristic of this species.

Of the Strix owls (large and round-headed) in the tropics, Mottled Owl is the most ubiquitous, being found from Mexico to Argentina and from the lowlands up to 2500m asl. I photographed this species at four sites on this trip. This photo was also taken at Huitepec on the same night as the Bearded Screech-Owl above.

The Black-and-white Owl was formerly placed in the genus Ciccaba but now merged into Strix (there has been a fair bit of merging of genera in owl taxonomy recently). Unlike the Mottled Owl however, this species sticks mostly to the lowlands. I took this photo at Cockscomb in Belize, a wonderful lowlands rainforest area.

Like the Mottled Owl, the Ridgway’s Pygmy-Owl is widespread and common. This species used to be called the Ferruginous Pygmy-Owl (and still is by the AOU) but the North/central American form (Ridgway’s) is now considered specifically distinct from the South American form (Ferruginous). I heard and saw this species at quite a few sites on this trip. This photo was taken at the ruins at Cobá.

Not an owl, but another exciting nightbird is the Northern Potoo. The potoos are a Neotropical family of nocturnal insectivores. It is amazing to watch such large birds sally forth from a perch in the night to pluck an insect from the air, like a huge nocturnal flycatcher. Their superb camouflage makes them difficult to find while roosting (almost completely motionless) in the daytime. In this case, I heard this bird calling just before dawn and followed them to their roost.

Well, this is a sampler but plenty more to come soon. I will also update my webpage soon. There are larger versions of the above photos available at
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