Strickland's Woodpecker

This handsome woodpecker is a male Strickland's Woodpecker, a shy and little studied Mexican endemic found only in a small part of the central volcanic belt of Mexico, where it occurs in open pine woodland above 2500 masl (Howell & Webb 1995).

Between 1983 and 2000, the AOU considered this and Arizona Woodpecker to be one species, the Strickland's Woodpecker. Arizona Woodpecker reaches down south through Mexico's central volcanic belt, and is replaced by Strickland's Woodpecker in central Mexico, where it has a very small, east-west range.

I found this bird yesterday on the slopes of the Cofre de Perote, a 4250 m peak near the border with Puebla. The high elevation makes for a completely different habitat and bird community, with many species common here that are not found in the coastal plain. Some familiar 'temperate zone' species become mountain dwellers here in Mexico, like for example Golden-crowned Kinglet, White-breasted Nuthatch, Brown Creeper, Loggerhead Shrike and American Robin. Here they are found with regional highland endemics such as Red Warbler, Collared Towhee, Yellow-eyed Junco, Mexican Chickadee, Striped Sparrow, and Gray Silky-flycatcher. Early yesterday morning I took the first bus to Perote, and from there a taxi up to a small community called El Conejo ("The Rabbit"), where the forest is mostly spruce and fir going up, and pines mixed with broadleaf going down. Located at about 3000 masl, it's quite a climb and I suffered a bit of altitude sickness when I got there, a dizzy spell that lasted about 30 minutes or so. It was worth it.

Cited literature:
Howell, S.N.G. & S. Webb. 1995. A Guide to the Birds of Mexico and Northern Central America. Oxford University Press, Oxford.

Olive-throated Parakeet

Besides Eurasian Collared-Dove, another species now seemingly much more common here in the coastal plain of central Veracruz than in previous years, is Olive-throated (Aztec) Parakeet. Noisy flocks of up to 20 individuals can be seen throughout the area. I'm pretty sure I saw them here in 2008 and 2009 also, but not regularly.

These past few days I saw them in La Mancha, in the fields around Chichicaxtle, and even in the town of Cardel.

 This Olive-sided Flycatcher, normally associated with middle and higher elevation pine-oak and evergreen forests, was a noteworthy find in the coastal dunes of La Mancha Saturday.

From rarity to dirt-common

This bird - a Eurasian Collared-Dove, of course - has steadily conquered North America ever since its first release in the mid-1970s in the Bahamas. It is still spreading rapidly, including into areas that already have a rich columbiform avifauna, like Mexico.

In central Veracruz, where I arrived yesterday for another fall season of hawk watching, this bird was still rare as recent as 2008. That fall was my first season here, and around the village of Chichicaxtle, where the Pronatura counters are housed and one of the two count sites is located, I saw it a few times in 2008. Then, in 2009, I found it to be regular in a few isolated spots.

Now, in 2011, this has become the most common dove in the area! Its three-syllable coo and its mewing display flight call is heard constantly throughout the community. That's no small feat in an area where pigeons and doves are both diverse and common.

In 1995, when Howell & Webb's Guide to the Birds of Mexico and Northern Central America came out, this bird was still unknown from the region.

eBird of course documents the spread of this species wonderfully. Watch an animated distribution map that starts with the period 1900-2000, followed by 1900-2002, 1900-2004, 1900-2006, 1900-2008, and finally 1900-2011.



Image provided by eBird (www.ebird.org) and created 17 August 2011.

Evidently, there were records from Central Veracruz as early as 2002, but the species didn't 'catch on' in the area until the late 2000's. eBird's filter still thought that the 12 Eurasian Collared-Doves I reported today was an "excellent count". I expect the regional editor will soon grow used to (perhaps tired of) approving high counts of this species in central Veracruz, and will adapt the filter.

I'm here for three months and expect to be entering quite a number of Eurasian Collared-Doves this season.

A mini-pelagic

Brown Noddy

Yesterday, Roselvy and I went on a mini-pelagic of sorts, when we boarded a small, open fishing boat and ventured about 5 nautical miles out from Los Cóbanos, on the Pacific coast of El Salvador. Time and money prevented us from going much further, so we didn't see many truly pelagic birds. That said, we did pretty well on this short trip with close looks at a Brown Noddy, prolonged close looks at two immature Brown Boobies, and distant views of two other booby species. The bad news is that one of those distant boobies was too far to pin down to species, and must remain a 'large, black-and-white booby', i.e. either Masked or Nazca Booby. We sighted the bird at some distance, and pursued it, without ever getting much nearer. Our pursuit was curtailed by an approaching booby that turned out to be an adult Brown Booby.

Brown Noddy

The third booby species, close enough for identification but too far for a photo, was Blue-footed Booby.

Brown Booby

The two Brown Boobies, one first-year-old and one older immature, hung around a buoy, where they allowed reasonable close approach.

Brown Booby

Black Tern was the most numerous avian species we encountered in these inshore waters. We encountered small groups of up to 20 individuals throughout the area.

Black Tern

We also saw about 25 dolphins and 5 marine turtles out there. Once back on land, while walking back to the bus, we found a pair of Yellow-winged Caciques in a tree that also had a Ferruginous Pygmy-Owl calling. This cacique reaches the southeastern edge of its range in El Salvador, and in that country is only known from this locality. 

Gray-crowned Yellowthroat

Gray-crowned Yellowthroat is a common species in agricultural areas throughout Mexico and Central America. It used to occur in the Lower Rio Grande Valley (Texas) but disappeared for unknown reasons around the end of the 19th century. Since the late 20th century, the bird has been recorded again irregularly in the Brownsville area. Population trends in Mexico and Central America are unclear, but the species may well be increasing, as it profits from land clearings for agriculture. It is often found in early successional grassy habitat and edge habitat, for example around sugar cane fields and in cow pastures.

In a group of very similar species - the yellowthroats of Central America - this bird stands out with its heavy, decurved, bi-colored bill, long tail and different behavior. Not a skulker at all, it likes to perch in the top of shrubs or trees, singing its charming, Blue Grosbeak-like song or giving its distinctive three-note call.

I recorded that call in the same field where I took this photo, through from a different individual. This was on the campus of Zamorano University, in central Honduras, east of Tegucigalpa.



The individual in the photos here, it will be noted, does not actually have a gray crown. It's probably a young male, based on the black, not slaty-gray lores that a female would have. Spring adult males (in alternate plumage) have mostly gray crowns, but in basic plumage the gray is much reduced to only the sides and forehead. On this particular bird, it appears to be completely absent.

Mexican birds have conspicuous eye arcs, much reduced or absent in Central American birds.

A Crested Caracara roost

This evening, while walking Oliver's dog Old Jack on the Zamorano University campus, Roselvy and I saw little groups of mostly two to four Crested Caracaras fly to what evidently is a roost here in the Yeguare Valley, in central Honduras. We ended up with a count of 21 caracaras, but we were not close to the roost site itself, and thus our count is likely not complete. We noted in which direction the birds were flying, and tried to follow them in binoculars for as far as we could, but distance and darkness made it impossible to see where exactly the birds landed. (These photos were taken here on campus yesterday.)

Although we tend to think of raptors as 'loners', communal roosting is known from various species, including Crested Caracara. A 1996 article in the Journal of Field Ornithology, for example, describes a roost in southern Guatemala where a maximum of 178 Crested Caracaras were observed roosting in a single large ceiba tree (Johnson & Gilardi 1996).

I don't know if the Yeguare Valley holds quite that many caracaras, but it would be worthwhile to try and locate this roost for a more complete count.

Cited literature:
Johnson, Matthew D. & James D. Gilardi. 1996. Communal roosting of the Crested Caracara in southern Guatemala. Journal of Field Ornithology 67(1): 44-47.

Zone-tailed Hawk: rare or not?

Today's post looks forward a little to what I'll be doing the next three months: participating in the world's biggest hawk migration census, in Veracruz, Mexico. It will be my third season there. One of the raptors that migrates through Veracruz is Zone-tailed Hawk. The first ones usually show up there late August. It then becomes an almost daily species in September. In Veracruz, the peak of their migration is during the last week of September and the first week of October, when double-digit days are regular.

Looking at the Veracruz River of Raptors dataset from the last 9 years, an increase from season totals of around 150 in the period 2002-2004 to totals around 250-300 for the period 2005-2010 is evident (source: www.hawkcount.org). Earlier, during the period 1995-2004, the season average for Zone-tailed Hawk at the site was 117.4 (Ruelas Inzunza, 2007). At least as a migrant in Veracruz, this bird clearly appears to be increasing.

Yearly totals Zone-tailed Hawk at fall migration counts in Veracruz, Mexico (2002-2010) [source: www.hawkcount.org]

Only northern populations undertake a southbound migration, and this increase at a major raptor migration census station likely reflects an increase of this northerly, migratory population.

These photos of an immature zone-tail were taken last month in El Salvador, where Zone-tailed Hawk is a fairly common permanent resident species. Like White-tailed Hawk, this is a widespread yet little studied species: the BNA account (Johnson et al. 2000) calls the status and distribution south of the U.S. "problematic", meaning little is known of those Central and South American populations. Indeed, their map seems incorrect: it shows southern Mexico and all of Central America as "winter only", with only a couple of small, isolated breeding locations in Nicaragua and Costa Rica. Big question marks on the map highlight this 'problematic' aspect of our knowledge of this species' distribution. Howell & Webb (1995) show a similar map, including the question marks, with the range for most of Central America as "winter only".

The most detailed and up-to-date, but still incomplete, information on the status of this species in Central America can be found in the species account of The Peregrine Fund's Global Raptor Information Network (or GRIN). This is what they have for Honduras:

Honduras: Probably a rare resident in the interior highlands. Breeding is as yet unconfirmed, and all records are from the winter months (Monroe 1968), except for one seen in April along the road from Tegucigalpa to Bonanza (Jones 2004). Jones (2005) noted that this species was being reported on average only once every two years on the Caribbean slope of Honduras, but by 2006, it was being reported more frequently (one to three times per year) (Jones and Komar 2006). Most likely, this reflects better coverage, rather than an actual increase in the number of zone-tails in the region.

My own impression is that this bird is an uncommon to locally fairly common resident throughout Honduras, including the lowlands. I have seen and photographed a pair with nesting material in the southeastern province of Choluteca in January 2010. On the campus of Zamorano University near Tegucigalpa, where I have been these past couple of weeks, I see adults and immatures almost every day. I have also seen this species elsewhere in Honduras, and am surprised to find how little has been published on the distribution of this species in Central America, and how rare it is reported to be.

Is this species really rare in Central America, or has it been under-reported? And if it's not that rare, is that a recent trend?

Cited literature:
Global Raptor Information Network: http://www.globalraptors.org/grin/indexAlt.asp
HMANA count data: http://www.hawkcount.org
Howell, S. N. G. and S. Webb. 1995. A guide to the birds of Mexico and northern Central America. Oxford Univ. Press, New York.
Johnson, R. Roy, Richard L. Glinski and Sumner W. Matteson. 2000. Zone-tailed Hawk (Buteo albonotatus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/529
Ruelas Inzunza, E. (2007) Raptor and wading bird migration in Veracruz, Mexico: spatial and temporal dynamics, flight performance, and monitoring applications - Dissertation University of Missouri - Columbia.