Sunday, November 13, 2011

Migrant and resident kingbirds of central Panama

During the northern winter, the resident population of Tyrannus kingbirds in Panama receives the visit of some others members of the same genus from farther north. Four different migrant Tyrannus have been reported for Panama, with two species that become particularly common around Panama City in central Panama. Despite it is only a passage migrant (doesn't winters in Panama), the Eastern Kingbird is the most common migrant Tyrannus in Panama. They typical are seen in huge and compact flocks during their passage through the isthmus, usually feeding only from fruits at the canopy of the trees. They fly over almost every kind of habitat in Panama. For obvious reasons, the translation of its spanish name is Northern Kingbird (the "eastern" part of its name makes no sense for us down here) and, definitively, this species is strongly associated with migration here in Panama. In contrast with our common, bright-colored species, the Tropical Kingbird, the Eastern KB exhibit a black-and-white pattern more reminiscent to the Fork-tailed Flycatcher. Of course, the Eastern KB lacks the long trail streamers; instead, it has a square tale tipped in white and has white markings in the wings. It also lacks the pale gray back of the Fork-tailed Flycatcher. Both, the Fork-tailed Flycatcher and the Tropical Kingbird, are VERY common in central Panama. Usually solitary, these two species often gather in really big flocks in relation to local movements, and even migration for the Fork-tailed Flycatcher. One of those unusual flocks of Tropical KBs initiated an interesting debate some months ago (you can read the story here). Not as common like the previous species, the Gray Kingbird is quite frequent in open habitats in central Panama. This is a migrant species, only present in our country during the northern winter. Mainly caribbean in distribution, this species also breeds in the mainland in southern Florida and in northern South America (Venezuela). You can tell apart it from the Eastern KB by its greater size, heavier bill and lack of black in the plumage or white in the tail. It also have a more large-headed look than the Eastern KB, making it more similar to our resident TK, specially under bad light conditions when you cannot distinguish its colors. All the species above mentioned are pretty common, surely due to their adaptability and availability of suitable habitat. However, the other two Tyrannus recorded for Panama are rare to very rare migrants to the western part of the country, though there are several records from central Panama as well. I still need to see a Western Kingbird, of which there is only a handful of records (the most recent here) and, till today, my only Scissor-tailed Flycatcher was an adult in the caribbean side of the Canal some years ago during a Christmas Bird Count. My distant photo does not do justice to the beauty of this bird...well, I guess I'll need to keep searching for these rarities!

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