Saturday, December 26, 2009

Last flock around La Esperanza

Today more Golden-cheeked Warbler shots, because today I was able to get many close-ups of these fantastic warblers. This morning we did our fifth and final flock here in La Esperanza, and if you've just tuned in and don't know what "doing a flock" really means: we're describing mixed warbler flocks in the pine-oak forests of Honduras, as part of a study of the winter ecology of the Golden-cheeked Warbler.

Again two individuals in today's flock, and again both of them adult males! This bias toward adult males so far is really quite remarkable. In this species, there is some segregation between males and females. The males tend to winter further north, in Chiapas (Mexico) and Guatemala, closer to the breeding grounds in Texas.

Here in Honduras, we're in the core winter range for this species, and in previous years females and immatures outnumbered males in this part of the winter range.

Last year's team found three adult males and eight adult females at this field site. This year we found five adult males, one immature male and one immature female. Keep in mind that adult females and immature males are very hard to separate in the field. For a discussion on how we separated those earlier two immature birds, see previous posts.

We saw both birds simultaneously, and thus were able to determine there were (at least) two adult males in today's flock. The flock was fairly small, and was comprised of 26 individuals, representing 16 species.

One of today's flock members was this 'female-type' (could be an immature male) Black-throated Green Warbler. This species is closely related to the Golden-cheeked Warbler, but shows an auricular patch on the face and yellow in the vent, which goldencheek never does. The upperparts are lighter on a BT Green - green, not olive - but in this underlit photo appear deceptively dark.

One site down, four more to go. Next stop national park Cusuco, on the Atlantic slope. We'll be staying in Buenos Aires, a small village in the beautiful mountains there. There is no electricity in Buenos Aires - never mind internet - so it will be a while until the next update.

No comments: