My dissertation, The Effects of Forest Management Practices on the Reproductive Success of Neotropical Migrant Birds in South-central Indiana.

Photo by Gabe Harp

The nest to the right belongs to a Wood Thrush (Hylocichla mustelina).  The blue egg is hers, as are the two hatchlings.  The brown-spotted egg was laid by a Brown-headed Cowbird (Molothrus ater).

Brown-headed Cowbirds are brood parasites, meaning they lay their eggs in the nests of other birds.  Many species of nesting birds will raise the cowbird young, suffering reduced breeding success as a consequence.

Human land use patterns affect the abundance and breeding success of forest birds.  For instance, the Wood Thrush tends to nest in mature forest. Cowbirds fly into the forest from roosting areas in the morning.  There they display and interact with each other and watch for potential hosts.  In the afternoon cowbirds fly to agricultural lands and lawns to feed, sometimes commuting 5 km or more between breeding and feeding areas.

Photo by Don Whitehead
The Acadian Flycatcher (Empidonax virescens) breeds in forests of the eastern United States and winters in Central and South America.  As with other Neotropical migrant birds, the population dynamics of this species may be affected by conditions in any part of its range.  

Clearing of tropical forests may affect survival over winter. Conversion of  migratory staging areas along coasts and large lakes to human land uses may affect migrants' chances of completing their strenuous flights. Fragmentation of temperate forests in eastern North Amerca may affect habitat availability and quality.

Some species of Neotropical migrants have shown declining trends in recent decades, as indicated by data from the Breeding Bird Survey.  Researchers are studying the demography of these species throughout the hemisphere.  My colleagues and I study how human land use patterns and forest management practices affect the abundance and breeding success of Neotropical migrant species, such as the Acadian Flycatcher and the Wood Thrush.