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Ruby-throats, a gardener's favorite

There exist about 338 species of hummingbird in the world, and all are found only in the Western Hemisphere. Of those, about 16 or so can be found north of Mexico. The great majority of that 16 are west of the Rockies, leaving us in the east with one representative: The ruby-throated hummingbird (Archilochus colubris).

Many birds can go unnoticed in the course of a person's day but hummers aren't in that group. Virtually everyone has seen one. These diminutive flyers are spectacular in their plumage and habits and tend to attract attention.

Male ruby-throats are about three to four inches long with a metallic green back, brilliant red iridescent gorget (throat) and white breast. It has gray flanks and a forked tail showing no white. Keep in mind, however, that its gorget may appear black under certain lighting conditions. The bill is long and needle-like. Females are slightly larger, with a longer bill. Females also show white in the tail. This time of year a person is more likely to see juveniles (which strongly resemble females) and females. If the throat cannot be seen, a more reliable field mark to differentiate the sexes is the absence or presence of white in the tail.

Males arrive first in spring and establish territories for themselves and await the coming of the females. Once mated, however, the female tends to the tiny, walnut-sized nest alone. Two eggs are usually laid and are the size of a pea. Once hatched, the young grow fairly quickly. At the time of fledging, the juveniles can be roughly twice the weight of the female due to the expenditure of energy she has put forth in tending her brood.

Migration is a marvel to begin with; doubly so with the ruby-throats. (Let's dispel an old myth here: hummingbirds do not ride on the backs of geese or larger birds while migrating). Most spend the winter in Mexico and Central America where their diet of nectar and insects can still be maintained. But getting there and back is a challenge. Both in spring and again in fall, many ruby-throats cross the Gulf of Mexico in one night, a trip of roughly 20 hours. During the crossing, about half its body weight is lost in a frantic dash to the shoreline. Flying non-stop just above the wave tops and with a heart beating up to 1,200 times a minute, these small birds are at the mercy of nature and weather. A single bout with an unexpected headwind can end the journey for many.

In addition to the Herculean effort of crossing the gulf, their size makes them vulnerable to other challenges. I've read of occasions where hummingbirds are caught and killed in spider webs. There are also reports of flycatchers nabbing hummingbirds and eating them as they would a large dragonfly.

But for their stature, these beauties pack a punch. Males, in particular, display an extremely aggressive attitude toward virtually any other critter that encroaches on its territory. This takes place at feeders, too. Once a hummingbird has claimed a feeder as its own it will vigorously defend it.

I don't live next to a river or heavy cover so I don't have nesting ruby-throated hummingbirds nearby. As a result, I only see them in spring and fall at the flowers and feeders. I usually tell folks to put their feeders out about the second week of August in our area. But I had a migrant in our yard just last week so its time to clean the hummingbird feeder, I guess.

While ruby-throats make up the vast majority of hummers in our area, it is possible to get a vagrant in your yard. In particular, rufous hummingbirds have a reputation for extra-territorial wanderings, as well as their close cousin, the broad-tailed hummingbird. Two recent reports from Mandan and Minot are probably rufous hummingbirds.

Until the first frost, we have a chance to witness the hovering, buzzing, backward-flying and flower-feeding of these avian jewels. And if you think you have something other than a ruby-throat, I'd like to hear about it.