By Ranger Steve Mueller
Here I Am, Where Are You? sings the Red-eyed Vireo all day long through the summer. Now it is silent but I watched one feeding on abundant insects this past week. Some years frost arrives by mid September but this year it is not expected until late October.
The olive back, white breast and belly of this long sleek bird is not often observed but it is one of the most abundant birds in deciduous forest. The bird spends much of it time high in trees or among the thick foliage. This past week one was lower to the ground gleaning food morsels on tree branches. I suspect it may have been a female because they are report to feed lower in trees than males. The two sexes look similar so I cannot distinguish them. I often wonder what food could be found on branches or among the leaves. When I look, I do not find many insects but the bird is looking thoroughly on twigs at very close range. Their eye focuses at one inch from the twig or leaf where it seeks food.
I once observed White-crowned Sparrows actively feeding in the lawn below my window but I could not see insects. I went out and got on my hands and knees. When I looked from only inches away, I could see many tiny insects flying about the grass. The birds were picking these tiny bits and making a collective big meal from them.
Vireos are about as long as sparrows but are slimmer. The vireo stands with an elongated body. When feeding, there is almost a straight line along its back from beak to end of tail. Most warblers hold their head up slightly so it is not in a straight line with back and tail. If one gets a good look, there is a white stripe over the eye with a black line before and behind the eye. If lighting is very good one can see the red eye iris for which the bird is named. The crown is dark above the light stripe over the eye. The stripe helps distinguish this vireo.
Vireos often nest low in trees and shrubs so one may encounter a nest. They suspend the nest in a fork where twigs diverge. The hanging suspended nest is a give away that it belongs to a vireo. I seldom find them during the nesting season but they are more obvious in winter.
Unfortunately nests are not hidden as well from Brown-headed Cowbirds. Cowbirds spend time watching the activities of other birds. When the vireo repeatedly enters a thick, the cowbird checks to see if a nest is present. When a nest is present the cowbird will lay an egg in the nest when the vireo is away feeding. The young cowbird hatches first and often pushes other eggs from the nest. It other young remain they often starve because the larger cowbird gets most of the food.
The bill of all vireos is heavier and longer that of warblers. It’s not thick and stout like the bill of cardinals, goldfinches, or sparrows. Its bill is well designed for capturing insects but the diet changes to include more small fruits in fall. By mid October few will not be found in these northern parts. They head for South America where they will be able to continue feeding on insects suitable for their nature niche.
Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at the firstname.lastname@example.org Ody Brook, 13010 Northland Dr, Cedar Springs, MI 49319-8433.