Last Autumn I Opened a Nest Box and Found It Crammed with Thousands of Small Bugs

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QUESTION BOX Renew or give a gift subscription BY KEVIN J. COOK to Bird Watcher’s Digest! SEPT/OCT 04 BIRD WATCHER’S DIGEST www.birdwatchersdigest.com www.birdwatchersdigest.com 1-800-879-2473

Nest Box WOES : Last autumn I opened a nest box and found it crammed with thousands of small bugs. They Q were about the size of ladybugs but longer and not so round. They were also olive green with a few black stripes. Should I expect them this year? What can I do to keep them out of the nest boxes? RAE BROWN, AURORA, COLORADO

: Your freeloaders were indeed insects but not bugs. In this case they are completely analogous A to birds. As animals, birds comprise a distinct class that divides into 30 orders. Likewise, insects comprise a class that also (coincidentally) divides into approximately 30 orders. Loons and owls are two separate bird orders in the same manner beetles and bugs are two separate insect orders.

All bugs are insects but not all insects are bugs.

“Ladybugs” are not bugs any more than “turkey vultures” are turkeys or vultures: They are, in fact, beetles. After years of persistence, entomologists are finally getting the name “lady-beetle” accept- ed.

Your description of size, color, pattern, and massing behavior perfectly fit the elm leaf-beetle.

The presence of the leaf-beetles clearly indicates you have Siberian elms growing in the general area. The grubs eat the leaves, making them appear like fragile doilies by late summer. After pupat- ing, the adults gather into any enclosed space where they can overwinter. In warmer areas, a sec- ond generation may be produced before the adults retreat to their winter shelter.

Attics, eaves, hollow walls, dog houses, poultry coops, old cars, clothesline poles, woodpecker cavities, and bird nest boxes are all commonly used sites. They might gather by the hundreds, by the thousands, or by the truckload. Those that don’t die during winter will disperse come midspring.

Siberian elms in the neighborhood guarantee elm leaf-beetles will always be around. You can keep them out of your nest boxes in two ways. Either take down the vulnerable boxes—those in proximity to the Siberian elms—or seal them. Plastic trash bags draped over each nestbox then secured with a turn or two of duct tape will do the trick.

After winter cold sets in, you can rehang the boxes or remove the plastic bags.

: Not seeing any activity around a large, newly hung nest box for a couple months, I decided to Qrelocate it. When I peeked into the box, I was surprised to see a layer of small gray-brown feathers on top of which, even more surprising, were three dead fish. They looked like odd goldfish. Surely kestrels wouldn’t catch fish and leave them in a nestbox, and I presume wood ducks would- n’t. What about kingfishers? RUDY ORR, COLUMBIA, MISSOURI : The evidence reveals all we need to know. No observed activity for two months suggests A something sneaky. Small brown feathers—I would bet they once belonged to several different European starlings—indicate the culprit likes eating small birds. And the fish could be either goldfish or koi, a common species of backyard ponds but not of elevated nest boxes.

You are correct: Neither American kestrels nor wood ducks would do such a thing. Nor would belt- ed kingfishers; they are quite finicky about wanting their nesting and roosting cavities at the ends of long tunnels.

Your mystery tenant was, without doubt, an eastern screech-owl.

Individual screech-owls develop certain appetites prompted by what is locally available and what they learn to catch as young birds newly independent from their parents. Some develop a taste for crayfish and subsequently leave crayfish shells and legs in tree crotches and nest boxes.

Screech-owls are also bold and talented poachers of ornamental fish that swim in backyard ponds.

Three fish in a nest box could represent a food cache established by a male during courtship, or they could represent a skilled and highly motivated male that caught more food than his family want- ed to eat at the time.

: A house wren discovered my bluebird box and made a real pest of itself. I spent all summer Q doing battle with the little twerp. It would start filling the box with sticks, and I would come along and empty the box. The routine was something between irritating and amusing! So, what can I do next year to keep the little nuisance out of the box? WANDA SHOTT, PEORIA, ILLINOIS

: Some things you can just rely on: sunrise in the east, taxes, gravity, house wrens filling little A spaces with sticks. You played right into the twerp’s plan. By filling a nonnesting space with sticks, the male wren dis- tracted you from bothering his actual nest.

Next nesting season, use his strategy against him. Hang a few more boxes to decoy and preoccu- py him away from your bluebird nest box.

Also, if you just let him completely fill the box once, which he will do, the completion of the task will satisfy him and he will turn his attention elsewhere. So long as you continually empty the box while he is in progress, the ever-empty space will stimulate him to keep filling. Let him fill it and become otherwise occupied before you empty it.

You can accelerate the process by putting something, such as a block of wood, in the bottom of the box to reduce the total amount of space that the wren must fill. Don’t use the block until you see the sticks inside the box that indicate the wren is at work again.

Mysterious SCAVENGER : We live in a rural area where a sizable shelterbelt flanks our house and farm buildings. While Q doing some routine cleanup around the trees, we found a nest the size of a beach ball. It was pretty messy and low in the crotch of a juniper. We first thought it was a hawk nest; but it was loaded with odd stuff like a few of our kids’ sandbox toys, clothespins, and some plastic forks. Would crows do this? AARON AND BACKA MILES, WICHITA, KANSAS

: The American crow long ago earned a reputation as a mischievous thief. Blue jays, Steller’s A jays, black-billed magpies, house wrens, American robins, common grackles, and house spar- rows will all snitch things that catch their eyes. However, these birds generally cache what they find or else just randomly drop it somewhere after carrying it off.

The Chihuahuan raven is a different matter. Famed for scavenging bits of wire, barbed and otherwise, Chihuahuan ravens incorporate many oddities into their nests. I’ve found bicycle inner tubes, automobile tow straps, and electrical extension cords.

But you live considerably east of the Chihuahuan’s range, and the site is all wrong. They typically build high above ground on windmills and power poles where they have clear views in all directions.

Your mystery nest was not built by a bird but by a fairly common mammal: an eastern woodrat.

Woodrats constitute a group of maybe as few as 8 species or as many as 10, depending on whose research you consult. The colloquial name “packrat” carries pejorative implications and is not used by mammalogists, ecologists, or naturalists.

You can easily distinguish woodrats of any species from Norway rats by their larger ears and completely furred tails.

All the woodrats build large mounds of any loose material they can carry. These mounds are not their nests but rather protective structures that house the nests. I prefer using the term “lodge” to describe the protective structure and “nest” to describe the actual living quarters within the lodge.

Eastern woodrats occupy a high proportion of the shelterbelts and windbreaks scattered across the southeastern and south-central Great Plains. Sometimes the lodges are built on the ground at the base of trees or draped over logs. Just as often, they are elevated above ground a few feet and snugly anchored in a tree crotch.

Completely vegetarian but somewhat selective, eastern woodrats are charming mammals that pose no threat to humans, pets, livestock, or the shelterbelt trees. Enjoy having them as neighbors; the great horned owls do!

Send your bird questions to Kevin J. Cook, c/o BWD’s “Question Box,” P.O. Box 110, Marietta, OH 45750 or e-mail [email protected]. (Please include a city or town and state or province with your questions.)