Nancy L. Newfield has been watching hummingbirds at her Louisiana home and lots of other places since 1975. Nancy lost her amateur status years ago, and now writes and lectures on hummers. She is co-author of Hummingbird Gardens, reviewed elsewhere on this site. Nancy is also a licensed hummingbird bander and a recognized authority on hummingbird distribution, behavior, and taxonomy.
Counting 'emIs there a crowd at your feeder? August is a month that many feeders are overrun with hummers. The nesting season has swelled the population while natural attrition has not yet taken its toll. There simply are more hummingbirds in August and September than there were in March, April, or May. If rainfall has been abundant, natural nectar sources will be at their peak - timed to fuel the extraordinary energy demands of the southward migration. Even so, there is never enough for everyone. Competition is the name of the game.
And, drought conditions may well reduce the blooming of wildflowers, thus creating a real energy crisis. At times such as these, feeders may well provide a margin of safety for hummers that can't find enough natural food. Young birds are especially vulnerable.
Crowded feeders are not necessarily an indication of a healthy population nor is reduced feeder usage a sign of population decline. Nevertheless, when the number of hummers vying for the feeders becomes too high to count, people try to devise methods for estimating their clientele.
Most estimates I've seen rely on the quantity of sugar used. This might be useful to assess the number of average-sized meals, but it does not take into account spillage of sugar-water or the fact that most of the hummers are getting food elsewhere as well.
My observations of uniquely color-marked birds have demonstrated that some individuals may drop in only once, never to return, while others may stay in the vicinity of a feeder for most of the day. Often, the hummers seem to have specific shifts of an hour or two.
A female Lucifer Hummingbird in the Big Bend country of west Texas travelled almost 1 1/2 miles from her nest to use a reliable feeder. She visited only 2 or 3 times each day. The remainder of her time was spent using other nectar sources and gathering bugs closer to her territory.
I estimate the number of hummers in a feeder location by counting the number that may be present at any particular time and then, multiplying by 4. My theory is that the birds need to feed about every 15 minutes, so only about 1/4 of the total clientele will be in attendance at any specific moment.
The idea came to me at the Reserve, Louisiana, home of Melvin Weber. He estimated that he had about 30 Ruby-throats frequenting his feeders, so I went to band them. At dawn we started capturing with mist nets and traps. Each bird was fitted with a numbered aluminum band issued by the U.S. Fish & Wildlife Service. A spot of white paint marked the crown of each banded bird so that we could distinguish those that were banded from those that were not. We didn't want to keep catching the same individuals over and over.
At the end of the day, I had banded 90 birds, yet the yard was swarming with hummers, only about a quarter of which were marked. So Weber's guestimate of his population was only a fraction of the number proven. 360 may seem like a lot of hummingbirds, yet we know that the 90 hummers banded were only a fraction of the total clientele.
Try this. Tally the number of hummers within view at any one time. If you have numerous feeders and if they are too far apart, you might have to get one or more additional counters. Then, total everyone's count and multiply by 4. I'll bet there's more than you think!
Copyright © 1996
Nancy L. Newfield