Two Butter Butts sally forth to capture flying insects.

It’s not unusual to see these warblers flycatching, after all, it’s how they make their living, eating insects. True, these warblers revert to eating fruits and seeds during winter, especially the wax myrtle fruit which is found throughout the Museum grounds, but when insects are available these little birds don’t hesitate to take advantage of their presence.

Myrtle Warbler about to consume a Wax Myrtle berry.

The question is, what were the flycatching Myrtles eating, what was it that they were catching in the tops of those pine trees?

The short answer is, I don’t know. I couldn’t see anything, even with binoculars, flying about the treetops. There must have been some sort of insect hatch, a fly of some kind which was too small to see from the ground. It was suggested to me by Richard Stickney of the Butterfly House here at the Museum that it may have been aphids, Giant Conifer Aphids (Cinara), that the birds were after.

This warbler is after some unseen (to me) flying insect.

Aphids are small (even the giant ones) and the Loblolly Pines are certainly conifers, so it could have been giant conifer aphids that I was NOT seeing flying around the treetops. But, I haven’t been able to find any information as to whether or not adults, winged adults, are present at this time of year, in mid February. Eggs may be present, and wingless adults or nymphs may be on the tree, but certainly, none of those would be flying out from the tree to be snatched up by the birds.

Calm, warm days are conducive to flycatching. Note the yellow rump on this bird.

The next day, the wind picked up and the birds were no longer flycatching from the pines. Any insects that ventured out from the tree would have been scattered by the wind.

Note: If any one out there has input into what the birds were catching on that beautiful blue-sky day in mid February, please feel free to send in your comments.

But first, some hints. This bird is only found in our area in winter (usually October through April). It is largely insectivorous but can switch over to fruit in the winter, especially the fruit of the Wax Myrtle. It will also eat poison ivy, greenbrier, juniper and other small fruits. The ability to switch over to seeds and fruit allows the bird to stay farther north in winter than many of the other members of its family. If this little gray-brown bird (it’s much brighter in color during the breeding season) visits your bird feeder it will most likely come to suet.

If you’ve been able to guess what the bird is from the very helpful hints above, great, if not here’s a photo:

This image may help you with the identity.

If you were able to identify the bird from the above image (and many useful hints), give yourself a pat on the back. However, if you’re still not sure…

The bird's most obvious field mark (the mark for which it gets its common name) is visible in this photo.

Still don’t know what the little bird with the yellow on its rump is?

Here's a side view of the bird. There's a yellow spot on the side of the breast and you can still see the hint of yellow on the "rump."

Well done, you’ve got it!

Although you may see Pine Warblers (year-round), and possibly a Black & White, Cape May, or Orange-crowned Warbler in winter at the Museum, one of the most often seen birds, and certainly the most often observed warbler at this time of year, is the Yellow-rumped Warbler. Simply stand in the proximity of one of the many plantings of Wax Myrtle (Morella cerifera) in Catch the Wind, Explore the Wild, or the Dinosaur Trail and you will see a Butter-butt (Yellow-rumped Warbler).

Wax Myrtle with its waxy fruit.

By the way, Yellow-rumped Warblers have two forms, “Audubon’s” Yellow-rumped Warbler in the west and “Myrtle” Yellow-rumped Warbler in the east. At one time they were considered separate species but are now lumped together as one. The eastern form was once known as the Myrtle Warbler after its fondness for Wax Myrtle.