The birds and beasts deserve a holiday, too, writes environmentalist Bill McKibben in Hundred Dollar Holiday: The Case for a More Joyful Christmas — “a day off from the hard work of finding food.”

So, on Christmas mornings he and his family take to the out-of-doors and scatter bread and seed.

“It is a mark of the bond we share with the rest of creation,” he writes.

Holiday spirit or not, December is the busiest month for the sale of birding supplies: seed, feeders, houses — and even birdbaths.

“A cold snap or a snowfall, and people suddenly have empathy for the birds,” says Thomas Franklin, co-owner with his wife, Cathy, of The Wildlife Authority in Ellicott City, Md. “They might not think about birds the rest of the year, but when winter comes, people get very interested in taking care of them.”

Birds that winter over are in critical need of three things, Franklin says.

• Food, because so many natural sources have disappeared until spring.
• Shelter in which to spend the night or escape harsh winds.
• Water for drinking and bathing, because their regular sources might be frozen and because their feathers must be clean to provide proper insulation against the cold.