Yesterday morning, both hummers hatched, after 17 days of incubation. This is on the long side of incubation times, and was probably largely due to cool-ish temperatures, although this female may spend more time off the nest than is typical for the species (below).
Contrary to the Birds of the World RTHU account, this female and the others I've observed begin continual incubation only after the second egg is laid, and the chicks do hatch synchronously.
It's easy -- and endearing -- to see the chicks' short yellow beaks and still-closed eyes as they stretch up to receive their mother's bill inserted deep into their gullets. Despite and because of daytime temps only in the 60's, Mom requires additional time to find the invertebrates she regurgitates for her young, and no doubt extra nectar to keep herself warm. So she's been off the nest for around half the time during the day, far more that the species account reports. Nevertheless, the chicks appear to be thriving.
Yesterday the female exhibited a behavior I've never seen or read about before. For a period of several minutes, encompassing 2 foraging departures and three bouts of incubating the hatchlings, she continuously vocalized with an "agonistic" (aggressive and/or alarmed) chipping call, similar to what we've all heard around feeders.
I couldn't identify what was alarming her, and it was quite surprising, because it certainly called attention to her and the nest.
The chicks will grow and develop at astonishing speed. Their eyes open at around 8 days, and they'll be fully able to forgo her body heat a couple of days later. They'll fledge about 20 days after hatching.
The photographic opportunities have been great, and I hope to post links one of these days soon!
Janine PerlmanAlexander Mt., Saline Co.
