The ‘bug’ that looks like a bird

Written by Jack Sanders
Thursday, 29 July 2010 15:42

From time to time, I get reports of unusual hummingbirds. Some, I suspect, are not birds at all, but “bugs” — more accurately, moths.

The Hummingbird Clearwing Moth or Common Clearwing (Hemaris thysbe) is among a couple of local species that can trick people into thinking they are hummingbirds. A look at the accompanying photo shows why: It has clear, fast-moving wings and a fat, colorful body like a hummingbird, and it hovers around flowers, just like a hummer. This species even has eyes that look more like those of a bird than an insect.

“I have my own regular pair of hummingbird moths that love my six-foot-tall butterfly bush by my pool,” says Erik Abrahamson of Ridgefield, who took the accompanying picture with a phone camera.  “I was also fooled into thinking they were baby hummingbirds, and even oddly looking like flying crayfish!”

Seeing a hummingbird moth makes one wonder: Did the insect evolve to look like a bird, or did the bird evolve to look like an insect? Or is the similarity just an accident of evolution for each?

In these cases, both moth and bird are designed to feed on and pollinate flowers. Flowers requiring pollination by agents (called biotic pollination) did not appear till about 200 to 250 million years ago. The first flying insects date from around 350 million years ago, but the first bird — said to be Archaeopteryx — took flight only 150 million years ago.

With a wingspan of about a foot and a half, Archaeopteryx had hardly a hummingbird-style wing beat. That took millions more years to evolve. Because hummingbirds are so delicate, and their bones so fragile, fossils are rare and hard to date. Guesses are that they may be only 2.5 million-years old.

So insects clearly had a head start on flower pollination, and the hummingbird came long after. If one were copying another, it would seem to be the bird.

But is anything actually being copied? In the tropics of North and South America, where hummingbirds evolved, there is considerable competition for food among uncountable species of birds, insects, mammals, reptiles, amphibians and other creatures. Being able to live off nectar from flowers well above the ground, such as those found on trees and on vines, seems to have been a niche that hummingbirds evolved to fill, even more efficiently than the ancient insects. Hummers learned to do things few other warm-blooded creatures can do — hover under or in front of a flower, for instance. And no other bird can fly backward, handy for maneuvering around large numbers of blossoms.

Perhaps hummingbirds evolved these insect-like talents in the same way bees and clearwing moths did — because that’s what worked best to get the food in the local environment. I have watched a Black-capped Chickadee hover as it dipped its beak into the end of a tube of a nectar feeder designed only for hummingbirds. Given enough eons, enough opportunity and enough hunger, a line of chickadees might evolve into a kind of hummingbird!

As for the hummingbird moth, it may be copying not a bird, but another insect. Many hummingbird moths have bodies that bear a strong resemblance to bumblebees, which wear bright yellow and black. This is apparently a design widely used among insects to warn would-be predators that danger waits in the form of a painful, perhaps deadly sting.  It is no coincidence that the clearwing moths also have such names as the Bumble Bee Moth or just plain Bee Moth. Of course, they don’t have stingers to match those namesakes.

Coming up

Milford Point & Great Meadows, in Stratford, birding trip with Brian O’Toole and others Saturday, Aug. 7, 9 a.m. to 2 p.m., $12/person, RSVP required to Brian at 203-869-5272 x221.

Trip to Jamaica Bay National Wildlife Refuge, early fall migration, Saturday, August 28, 8:30 a.m.  to 2:30 p.m., $5 (kids free), carpooling from Millwood, N.Y., Saw Mill River Audubon, 914-666-6503  This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Sharon Audubon Festival, nature walks, bird programs, music, food, displays, Saturday and Sunday, Aug.14 & 15, 9: to 5, 860-364-0520, sharon.audubon.org.

Birdwatching cruises of the Norwalk Islands, aboard the new 45-foot C.J. Toth ferry, three hours, Saturdays,  Aug. 7, 21; Thursdays, Aug. 5 and 19, at 7:30 a.m., $22 adults, $12 kids,  Norwalk Seaport Association, Seaport Dock,corner of Washington and Water Streets, South Norwalk, reservations, 203-838-9444.

Copyright 2010 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] yahoo.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877; or call 203-438-1183, extension BIRD (2473), and leave a message with your report, spelling your first and last names and telling us your town. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s website is www. sandersbooks. com.