A White-eyed Vireo Nest

The following piece is about an interesting discovery from last summer.  I couldn't resist sharing a little about these birds!

Have you ever had to remove a wasp from the house?  While I normally hold nothing against the industrious little predatory insects, it's frustrating to deal with them when they decide to leave their natural environment and invade mine, instead.  Fortunately, this particular intruder—which had been flying erratically around the dining and living rooms before finally retreating to the living room window blinds—turned out to be a relatively easygoing, harmless mud dauber, not one of the more aggressive red paper wasps building nests above the front porch.   Whew!  Easier to capture and release.

As I was catching the mud dauber, I happened to notice a White-eyed Vireo perched in the thorny elaeagnus (also known as thorny olive) shrub growing next to the window.  Then I saw the nest, a papery, woven pouch about four or five inches deep, suspended from the crotch of a twig.  This was the closest I had ever been to an active vireo nest—close enough for me to appreciate the tight construction of insect and spider silk, grasses, bark strips, and other materials.

The nest, with a wary -- and hot -- White-eyed Vireo!

The silk webbing that serves as the foundation for vireo nests is probably what makes them so durable.  I’ve noticed that vireo nests tend to hold up very well even months after the nesting season is over.  I have seen a few empty nests in decent condition, most recently a probable White-eyed Vireo one on Mississippi State University property, winter 2014, and what I suspect was a Bell’s Vireo nest at Frog Bayou Wildlife Management Area in northwestern Arkansas, summer 2014.

2014 Bell's Vireo nest -- Arkansas

Active nests are generally much more exciting to observe than old ones, though, and the White-eyed Vireo nest in the thorny elaeagnus was no exception.  Although I had not noticed any nesting activity earlier in the year, I was aware that adult vireos were probably already raising their second brood of the season.  White-eyed Vireos typically arrive in the northern half of Mississippi by early April, and, according to "The Birds of North America Online" (http://bna.birds.cornell.edu/bna/), they take three to five days to complete a nest, one day to lay each of the three to five eggs, thirteen to fifteen days to incubate eggs, and nine to eleven days to raise nestlings.  Given the birds’ typical arrival dates and the rapid development of the young, June 15 would probably be unusually late for a pair to still be working on a first brood.  

 

Because the nest was such a deep pouch, I initially had trouble seeing into it to determine whether eggs or young were present.

Once I began to observe the parents bringing various insects to the nest site, it was obvious to me that there were nestlings.  Caterpillars, small wasps, and beetles were among the species that the vireos stuffed into the yellow maws of their offspring.  For the first two days, June 15 and 16, the parents made these feeding trips at intervals of approximately 10 to 20 minutes.  Feeding seemed to slow down a bit over the next few days.  I suspected that these nestlings were already a day or two old on the 15^th, and my later observations seem to bear that out.  Interestingly, one egg had failed to hatch.

Vireo young and unhatched egg on June 21, 2016

The nestlings developed quickly, becoming noticeably larger, sleeker, and more alert each day.  The photograph below was taken only a day after the previous one.  The infertile egg was still there, too—just hidden under the young birds.

June 22, 2016

On June 22, the birds were ready to fledge.  I missed watching the first one, which apparently left the nest sometime in the late afternoon.  The second bird stayed for a while longer, but by the end of the day, it, too, had fledged.

Over the next couple of months, the vireos—both the adults and the fledglings—chattered, foraged, and flew around the shrubs near the house.  Juvenile White-eyeds have dark brown eyes during the summer, making it very easy to distinguish them from their parents.  They begin to live up to their moniker in late fall or winter, when their irises permanently turn white.  By that time, they and their parents have most likely left for their wintering grounds in Central America, the Bahamas, Bermuda, or, in some cases, the southeastern portions of North America.  I'll be watching for them again this year.