We have conducted several cycles of mist netting studies of the birds of Laguna de Apoyo Nature Reserve in Nicaragua, where there are tropical dry forest habitats facing several levels of human intervention. We have noted how several species of birds can be found commonly in one of our study sites but rare or almost not at all in another site of different vegetation structure and composition. The following are a sampling of the migratory birds that appear in our nets in our studies.
|Indigo Bunting (Passer cyaneus) males are not nearly so spectacular on the wintering grounds as they are during breeding season. Photo Pier-Oliver Boudreault.|
Laguna de Apoyo Nature Reserve offers winter habitats to many migratory bird species which nest further north. One example is the Indigo Bunting (Passerina cyanea), which nests as far south as extreme northern Mexico, but all the birds of this species disappear move southward into a range extending from central Mexico , the southern tip of Florida, throughout the Antilles and to Panama.
The male Indigo Bunting is appropriately named for its attractive, practically solid blue coloration exhibited during reproduction. A feather molt in the fall, however, leaves the males with mostly drab, brown color, with some deep blue highlights. Hence, the male Indigo Bunting only uses the bright colors during reproduction and maintains a muted appearance when in Nicaragua, which may be driven by predator avoidance and possibly direct physiological costs to produce and maintain the bright plumage.
The female Indigo Bunting is never brightly colored, and lacks the blue wash seen in the male when not in reproductive plumage. Many bird species use color dimorphism in which males demonstrate their reproductive fitness with bold colors and plumage as secondary sexual characteristics which the females use in mate selection. Presumably, a male which will sire offspring more successfully will also have a nice wardrobe.
|This male Indigo Bunting is an adult with well-developed flight feathers, with rounded tips. Photo Pier Boudreault.|
|This female Indigo Bunting insisted on a fight so she got one-with the stem of a leaf. Photo Pier Boudreault.|
|Female Black-and-White Warbler. Photo Vera Neumann.|
|Wood Thrush. Photo Pier-Oliver Boudreault.|
|The Swainson's Thrush (Catharus ustulatus) is frequently captured by mist nets in appropriately shaded habitats in Laguna de Apoyo Nature Reserve. Photo Pier-Oliver Boudreault.|
Another family of migratory landbirds consists of the tanagers, which are distributed into multiple families in spite of similar external characteristics. The Western Tanager (Piranga ludovicianus) has recently been placed in the cardinal family (Cardinalidae). It is less common than the Summer Tanager (Piranga rubra), and has a similar but less melodic, more raspy call on its winter habitat. The Western Tanager tends to stay close to the top of tall trees, coming down to lower levels only occasionally, for which we have relatively few capture records.
The mature male Western Tanager has a red head which fade to yellow neck and throat and olive-yellow body, over which bold black markings are found on the wings. The females lack red on the head and have fewer wing markings. As in many species, the males attain adult plumage after the first winter season, during which only vestiges of the adult male color pattern are noted. This species prefers more well-developed forest structure in Laguna de Apoyo Nature Reserve.
|Immature male Western Tanager. Photo Vera Neumann.|
|Sulphur-bellied Flycatcher (Myiodynastes luteiventris). Photo Marlene Krone.|
|Sulfur-bellied Flycatcher. Photo Vera Neumann.|
|Click on the "escudo" to contact us.|