"Swirling air can make hummingbirds work harder to hover, but only when the air’s vortices open wider than a bird’s wing.
The first measurements of how much a flying animal’s metabolism revs up when coping with turbulent air come from five Anna’s hummingbirds (Calypte anna) that Victor M. Ortega-Jimenez of the University of California, Berkeley and his colleagues tested. In a wind tunnel, the hummingbirds hovered at a feeder downwind from a cylinder of varying size. Buffeted by vortices of air whipping off slim cylinders (2 or 4 centimeters in diameter), the birds held their position without needing extra oxygen even with wind speeds of 9 meters a second, or about 20 miles per hour.
But when researchers used a 9-centimeter-wide cylinder, vortices widened to 173 percent of wing length. This time hummingbird metabolisms increased some 25 percent on average — even at gentler wind speeds of 3 and 6 meters per second. The hummingbirds relied on asymmetric tail and wing motions to hover in place, the researchers report March 26 in Proceedings of the Royal Society B.”
"The Common Poorwill (Phalaenoptilus nuttallii) is a nocturnal bird of the family Caprimulgidae, the nightjars. It is found from British Columbia and southeastern Alberta, through the western United States to northern Mexico. The bird’s habitat is dry, open areas with grasses or shrubs, and even stony desert slopes with very little vegetation.
Many northern birds migrate to winter within the breeding range in central and western Mexico, though some remain further north. Remarkably, the Common Poorwill is the only bird known to go into torpor for extended periods (weeks to months). This happens on the southern edge of its range in the United States, where it spends much of the winter inactive, concealed in piles of rocks. This behavior has been reported in California and New Mexico. Such an extended period of torpor is close to a state of hibernation, not known among other birds. It was described definitively by Dr. Edmund Jaeger in 1948 based on a Poorwill he discovered hibernating in the Chuckwalla Mountains of California in 1946.”