Saturday, December 31, 2011

White-breasted Hawk

adult male White-breasted Hawk, Honduras, December 2011
White-breasted Hawk is a little known raptor from the Central American pine-oak forest. Officially (AOU) still a subspecies of the Sharp-shinned Hawk, most authors agree that this form should really be its own species. Currently, ten subspecies of Sharp-shinned Hawk (Accipiter striatus) are recognized, which can be subdivided in three main groups: the striatus (Sharp-shinned) group which contains four subspecies on the North American mainland and three island ssp; the Central American chionogaster (White-breasted) group with just one subspecies; and the erythronemius (Rufous-thighed) group with two South American subspecies (Bildstein & Meyer 2000). Future DNA work is likely to result in a split into at least three species: Sharp-shinned Hawk; White-breasted Hawk; and Rufous-thighed Hawk.

tail of adult male White-breasted Hawk, Honduras, December 2011
We caught this adult male while banding in Monte Uyuca (Honduras) last week. We have been banding there every month for two years now, and regularly see White-breasted Hawks around the net lanes. This was the first time we caught it here. Note (browner) retained outer rectrices from a previous molt generation.

Upperside wing ad male White-breasted Hawk, Honduras, December 2011
Upperside wing shot. Note the difference in (browner) retained primary coverts compared to (slaty) fresher secondary coverts.

adult male White-breasted Hawk, Honduras, December 2011
After we released the bird, it perched in a nearby tree. It may be worth noting that the tibial feathers appear white, like the rest of the underparts. Bildstein & Meyer (2000) describe light ochraceous-buff tibial feathering for the adult White-breasted Hawk...

juvenile male Sharp-shinned Hawk, Honduras, December 2011
Another first for the site was this juvenile male Sharp-shinned Hawk. We caught it two days later during the same pulse.

juvenile male Sharp-shinned Hawk, Honduras, December 2011
White-breasted Hawk is a resident species here in Honduras; Sharp-shinned Hawk is a winter visitor to the region.

Bildstein, Keith L. and Ken Meyer. 2000. Sharp-shinned Hawk (Accipiter striatus), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online:

Monday, December 19, 2011

A Prairie Merlin in Honduras

Adult male Prairie Merlin, Campus Zamorano University, Honduras, 18 December 2011
Yesterday, while birding the Zamorano University campus in central Honduras with Paul Stufkens, my friend Oliver and I found an adult male Merlin of the Richardson's or prairie subspecies. The Global Raptor Information Network (GRIN) calls the Merlin an "uncommon migrant and rare winter visitor (columbarius) in the lowlands of both coasts and in the Caribbean islands off Honduras", citing Monroe's 1968 Distributional Survey of the Birds of Honduras. eBird has few records for this species in Honduras, although I suspect that Merlins are probably regular along both coasts in migration and perhaps uncommon, but not rare, in winter.

But a Prairie Merlin this far south is spectacular!

Merlin, a species found in North America, Europe and Asia, has three distinct populations in North America: the highly migratory Taiga Merlin (columbarius) of the northern forests, the sedentary Black Merlin (suckleyi) from the Pacific Northwest, and the partially migratory Prairie Merlin (richardsonii) of northern prairies and aspen parkland. The latter form winters from extreme southern Alberta and Saskatchewan southward to the area bounded by eastern California, northwestern Mexico and central Texas (James et al. 1987). Thus, it is resident in parts of its breeding range, with the majority undertaking a relatively short migration into the southern Great Plains (Temple 1972).

It is much paler overall than the taiga Merlin, and has the light bands on the tail much wider than in that subspecies.

I realized this was a noteworthy sighting, and I expected our Central American record of this subspecies to be perhaps unprecedented, but it turns out that eBird has a record for northern Belize - from just 5 days prior! On 13 December 2011, Lee Jones and Roni Martínez reported a female or juvenile of the prairie subspecies in northern Belize, noting it was significantly paler than the taiga Merlins these observers normally see in Belize.

records of Prairie Merlin in eBird (recent records in red) - data courtesy of eBird
So... these two recent records beg the question: Is there currently a small-scale influx of Prairie Merlins going on into Mexico and Central America? It will be interesting to see if more individuals of this subspecies get reported in the coming weeks from the region.

Cited literature:
James, Paul C., Alan R. Smith, Lynn W. Oliphant, Ian G. Warkentin (1987) "Northward expansion of the wintering range of Richardson's Merlin" Journal of Field Ornithology 58 (2): 112—117.
Temple, Stanley A. (1972) "Systematics and evolution of the North American Merlins" The Auk 89: 325—338.