Thom Smith: Luna moths' final act


Q: In the last two days, dead luna moths have been found (in perfect condition) in Lanesborough and South Woodstock, Vt., and in The Eagle on B2 today [June 16]. Anything peculiar here? -- Paul, Lanesborough

A: Perfectly normal. The emergence was an early Father's Day gift; the deaths were (are) perfectly normal.

When the time comes for the luna's final act, it pushes its way out of the pupa where it has changed from caterpillar to adult moth, taking about three weeks. Emergence usually happens in the early part of the day, allowing time for its spectacular wings to fully expand and dry before evening when activity begins, and shortly after midnight they mate. Having only vestigial (non-working) mouth parts, they do not feed and are short-lived.

Q: We have had such enjoyment from a pair of bluebirds. We watched them select their house, not too far from our porch. Every evening we enjoyed their coming and going, knowing that they must have been sitting on eggs. Two weekends ago, we were sure that we heard the babies peeping, parents busy in and out. Then no bluebird activity. Sadly, we noticed that flies were flying into the box. We opened the box and found three baby birds, with feathers, all dead. No further sign of the parents. What could have happened? We cleaned out the box. Will they return? -- Irene, South Lee

A: "It is a jungle out there!" And while the predators may not be tigers or lions, but "cute" little English sparrows that are not true sparrows at all, but weaver finches. For many, they are unwelcome aliens and do plenty of harm, driving off native species, destroying their eggs and even killing nestlings. They are often described as rats with wings. What is worse, is they will kill roosting bluebirds, and last summer I saw evidence of this first hand.

As a matter of fact, the house or English sparrow may well be the No. 1 enemy of the bluebird. English sparrows are non-native invasive pests and are not protected by U.S. federal law. Their nests, eggs, young, and even the adults, may be legally removed or destroyed. Those who manage bluebird trails (a name for a series of bluebird boxes) say, "It is better to have no box at all than to allow English sparrows to reproduce in one."

The decline in population of eastern bluebirds may have begun in the early 1920s due in a very big part by competition from other cavity nesters, the English sparrow and the European starling, as well as possible changes in tree management, like removing dead trees that offer nesting sites, and of course increased use of pesticides including DDT. Today, the bluebird has recovered and is a common species, preferring open areas like parks, fields, orchards, even gardens and neighborhoods. The monumental increase in providing nesting boxes attracts them and is an important factor in there greater abundance today.

As for cleaning out the box, in this case, with flies being attracted, I believe you made the correct choice. It is thought by some that leaving the nesting material might encourage the birds to do a little house cleaning, add some fresh material and resume nesting in less time.

While I focused on one probable culprit, weather should also be considered.

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