Hummingbirds keep singing as season wanes

We now resume our regularly scheduled programming: “common backyard birds and their life histories.”

It’s that time of the season again – the rush of spring and returning migrants is over. Breeding and fledging young has commenced and in many cases concluded. Which means things are a lot quieter. Many of our avian neighbors are not quite as focused on defending territories and securing mates, filling the air with song. Instead, they are now more preoccupied with raising young and fattening up for southward migration.

The tree swallows in our nest box have fledged young and all seem to have departed from the area. The chipping sparrows also seem to have dispersed. Our resident woodpeckers don’t visit the feeder as often; when they do, they are no longer accompanied by begging fledglings.

I was commiserating about the diminished bird song and activity with co-worker Paul Markson, who also enjoys birds and birdwatching. But I realized there was one bright spot – literally and figuratively – when he said, “At least the hummingbirds are still around.”

Thank goodness for hummingbirds! Somehow, they made it through the cold and rain of spring. I’m not sure if they’ve managed to raise any young yet, but the season may still be young for them; there is a record of egg-laying as late as Sept. 2 – in Ontario, no less. It’s even possible they may produce two broods per season.

I hope someday to see a hummingbird’s nest, which would be about the size of half a walnut shell. (The eggs are pea-sized; two can fit on the surface of a penny). Ruby-throats may nest in a number of different tree species: oak, yellow birch, poplar, or pine. It is the female that does all the building. She collects the plant down of thistle and dandelion, lichens, and bud scales, and intricately weaves all the materials together with spider webbing. She selects a site beneath overhanging foliage, often building at the tip of a down-sloping branch, which itself is sometimes near or directly over water. Ideally, there should be a nearby source of nectar and insects, for it is she that takes on the sole responsibility of incubation, brooding, and feeding her young. Not to mention feeding herself.

Hummingbirds are pretty antisocial. Males may mate with multiple females but do not assist in any way with raising young. They will chase females as well as other males away from prime nectar sources.

A typical clutch size is two eggs; sometimes three eggs may be laid. Incubation lasts up to 14 days and the young emerge completely naked. They leave the nest when they near 22 days old and continue to be fed by the female for up to a week longer.

Many people provide artificial nectar so they may enjoy hummingbirds up close, but providing nectar-producing plants is far more preferable. Feeders must be meticulously maintained as the sugar-water solution (four parts boiled water to one part sugar) ferments rapidly, especially in warm weather; this, plus the growth of mold and bacteria in the solution, can be very harmful to the birds. A good guideline is to clean and disinfect feeders every 2-3 days (more often in very warm weather), in a 10 percent bleach solution. Rinse well and allow to air dry before adding fresh, cooled sugar-water. Keep unused solution refrigerated, and discard after one week. Do not add red food coloring as this is unnecessary and may actually be harmful.

The information in the preceding paragraph was gleaned from the University of Maine Cooperative Extension bulletin, “Understanding ruby-throated hummingbirds and enhancing their habitat in Maine.” This is a comprehensive guide to their annual cycles, biology, habitat requirements, favorite nectar-producing plants, and landscaping suggestions. I’d recommend it highly to anyone interested in hummingbirds. Visit http://extensionpubs.umext.maine.edu/, click on “Gardening and Horticulture,” and do a search for “hummingbirds.”

Another good Web site dedicated to research of ruby-throats is http://www.nehummers.com, where you can log your own sightings of hummers visiting your yard.

NEWS bird columnist Chris Corio can be reached at bdnsports@bangordailynews.net