For many years right around Memorial Day, I have received reports from homeowners throughout the state reporting the numbers of hummingbirds visiting their feeders dramatically increase. Although it is great to have squadrons of rubythroats zooming around our yards, many hummingbird experts are scratching their heads trying to figure out why the birds are so abundant at that time of the year. This year is no exception.
The first ruby-throated hummingbirds begin arriving throughout much of Georgia in late March. Typically, at this time of the year it is unusual to host more than two to four birds at a time. At the peak of migration, you are lucky if you see six of eight of these aerial acrobats in your backyard. Most of these linger only long enough to refuel before resuming their migration to points north.
Once the migration has passed males and female scatter across the countryside and settle into breeding territories that possess a combination of suitable nesting sites and ample food supplies. Once a male chooses a section of real estate, he spend the rest of his time trying to attract females. These breeding territories rarely exceed an acre to two. Consequently, if a male doesn’t select a territory that includes your yard, you might not see any hummers visiting your feeders for a month or two.
If another male hummingbird happens to venture into a male’s breeding habitat, the interloper is attacked and usually driven off. For this reason, during the peak of the breeding season, you are not apt to spot more than one ruby-throated hummingbird male using the same feeder.
While male hummers are beating up on one another, the females are busy with the serious business of either incubating a fragile clutch of black-eyed pea-sized eggs or raising their first brood of the year. During the 10-12 days that females are incubating eggs, they spend most of their time on the nest. As such, they have little time to visit feeders.
Once the eggs hatch, females are kept extremely busy finding enough food to feed their young. During the approximately three weeks the young are preparing for their first flight, females are foraging for nectar as well as small, soft-bodied insects and spiders. These animals provide the much-needed protein necessary for the development of the young. As you might expect, females will visit our feeders more often during this time.
Since most of the state is in the peak of the ruby-throated hummingbird nesting season, I think you can see why it is seems odd to have swarms of hummingbirds patrolling our feeders right now. Some suggest perhaps this invasion is due to the fact hummingbird nesting was early this year, and the year’s first brood are now joining their parents at our feeders. However, based on my observations, this theory doesn’t hold any water. My banding efforts in prior years during this time frame revealed that all of the birds I captured in my backyard were adults. This year, although I have not done any early banding, I have not seen any immature birds at my feeders.
Another possible explanation is these the birds are late migrants. This seems unlikely since some rubythroats actually begin their southward migration in July. This leaves precious little time for the birds to reach their nesting grounds, establish breeding territories, and raise their young. However, since very little hummingbird banding is conducted at this time of the year in the Peach State, this theory cannot be disclaimed or proven.
A more plausible explanation is this dramatic change in hummingbird behavior is linked to another extremely dry spring. Once again, this year Georgia was treated with winter temperatures that were well above normal.
As a result, flowering plants bloomed much earlier than normal in many parts of the state. This was followed by increasingly dry conditions throughout much of April. A lack of rainfall has persisted throughout the month of May. This has further reduced the number of nectar-rich blooms available to hummingbirds. According to this theory, this situation has created a food shortage for hummingbirds and other nectar feeders. Even in the best of times, a hummingbird must often venture far and wide to feed themselves and their young. Our feeders offer hummingbirds with abundant sources of food that can be obtained with little effort.
If this is the scenario that is playing out this year, it will be interesting to see how this affects the success of the birds’ first nesting efforts. In the meantime, if hummers are not currently swarming around your feeders, be patient. Hummingbirds will be jousting with each other around your feeders in about a month. If, on the other hand, you are lucky enough to have hummingbirds draining your feeders daily, don’t worry about why they are there, just sit back, and enjoy the show.