Soon waves of migrating neotropical birds will pass through our area. They will be feeding furiously on hatching insects in the tree tops this May, but some have already arrived and have been here for weeks.
Eastern Phoebes (Sayornis phoebe) flew in from the southern United States and from as far south as Mexico, where about a third of these flycatchers spend the winter. Some Pine Warblers (Setophaga pinus) are permanent residents in Florida, Georgia, and the Carolinas. Many winter as far south as eastern Mexico and the Caribbean and migrate north in the spring. One of the most common wintering neotropical migrants where I sometimes vacation in southwest Florida is the Palm Warbler (Setophaga palmarum), a species that also winters in the Deep South and the Caribbean Islands.
Why do these insect-eating birds arrive so early? Eastern Phoebes come here as early as March, occasionally even when ponds are not free of ice. Pine and Palm Warblers arrive a few weeks later. It may be that arriving early is an advantage for these species that lets them claim open nesting territories. But this sometimes comes with a price. Late winter and early spring snowstorms could prevent them from finding food.
The large, explosive spring hatches of flying insects and moth larvae haven’t happened yet, so what are these birds feeding on? Most of the Eastern Phoebe’s diet is made up of flying insects, but they also eat spiders, ticks, and millipedes, and occasionally small fruits and seeds. Pine Warblers poke through bark, needles, and pine cones looking for dormant insects and early arriving birds are often seen searching through leaf litter for insects and other arthropods. They will also eat seeds and berries. Although Palm Warblers glean insects off tree bark and jump up for flying insects, they habitually feed on the ground and can even be spotted foraging there with sparrows. They will also eat bayberry (Morella pennsylvanica) and hawthorne (Crataegus spp.) fruits. So, an advantage these early migrants have is that they are adapted to finding food on the ground and eating fruits and seeds.
The Eastern Phoebe and Pine Warbler both nest in Connecticut, but the Palm Warbler is just passing through. It nests farther north usually on the ground in tamarack (Larix spp.) bogs of the boreal forest.
The Eastern Phoebe can be identified by its slate gray back and relatively large, dark head. It also wags its tail up and down. This bird gets its name from the song of the male: a raspy “fee-bee”.
The Palm Warbler also pumps its tail up and down. Both these birds and phoebes are among the few species that do this. The adult has a gray back, rusty coloring on the crown (top of the head), and rufous-colored streaks on its yellow belly. Its song, a weak, buzzy trill, is not frequently heard.
The Pine Warbler also has a yellowish belly, but its wings are gray with white wingbars and it has a yellow ring around its eyes. There are indistinct olive streaks on the sides of its breast. The male’s song is a long, liquidy trill.
Before migrating, these birds build fat reserves up to 50% of their body weight. Once these reserves are used during migration, the birds need to stop and refuel. Dave Ewert, senior conservation scientist with the American Bird Conservancy, describes three kinds of habitat that migrant birds look for.
“Fire escapes” are used in times of stress when birds are exhausted, starving, or disoriented. Under such emergency conditions, they stop at any habitat they can find. Small patches in urban and industrial areas can be fire escapes for migrants.
“Convenience stores” offer more abundant and higher-quality food and shelter, and are larger than fire escapes. Birds prefer them over fire escapes if they have a choice. Suitable habitats in parks, suburban gardens, and isolated rural woodlots are important convenience stores for migrants.
“Full-service hotels” are sites with the best habitat—plenty of nutritious food for refueling, safety from predators, and adequate shelter from inclement weather. These sites are natural areas, undeveloped rural lands, parks, and relatively large wildlife refuges.
Whether you live near a fire escape, a convenience store, or a full-service hotel, plant native perennials, shrubs, and trees that attract insects. Think of your yard or nearby park as a thing of beauty, not only because these plants are attractive to us, but because they are important refueling stops for these colorful birds.