Water is the most important thing you can give birds in winter.

This is being written at noon on Jan. 2, outdoor temp -8°F. Water, at least in our western suburban neighborhood, has to be next to impossible to find.

Except in our heated birdbath, seasonally misnamed because it's mostly a watering hole in winter. All of our feeder birds except woodpeckers use it.

Humans can live for two weeks or longer without food. No water for three days and you're a goner.

I can't find comparable numbers for birds. Certainly the time periods are much, much shorter, particularly for smaller birds.

I have Cornell's "Handbook of Bird Biology," Cornell's "Manual of Ornithology (Avian Structure and Function)," and the resources of Google Scholar, where you can find research papers for almost any subject you choose.

They offer much information on birds and hot weather, not much on winter water needs.

I have learned that when a bird exhales on a cold day it first removes and uses the water vapor included in that breath. It does the same for its waste, removing water before the void.

Also, birds cannot get along by eating snow. Melting the snow once ingested takes way too much energy.

What is the impact of a cold dry day like this one? Humans are advised to stay hydrated. We use humidifiers and lotions and oils and creams to keep our skin from drying out.

A Web entry discussing care of caged birds, like budgies, firmly tells bird owners to keep a humidifier running in any room occupied by those birds. What the birds lose to evaporation would have to be replaced.

A study on chickens (Journal of Agriculture Science) found that they lost 25% of their water to whole-body evaporation when the air temperature was 104°F. When the temp dropped to 32°F the loss of water increased to 78%.

Bird feathers do provide some protection in that regard, according to Cornell.

Birds can get water from their food. Nestlings never see water until they fledge. They get water from the bodies of the insects they are fed. Adult birds do the same, except, of course, in winter.

The food in your bird feeders, dry as it is, does provide some water.

Metabolism produces water as a byproduct. A gram of protein is good for 0.4 grams of water, gram of carbohydrate contains 0.56 grams of water, a gram of fat (think suet) 1.07 grams of water (0.066% of a tablespoon).

This might explain why our regular woodpecker visitors have not been seen drinking here: They eat a lot of suet.

Some birds conserve water and energy by using hypothermia to lower body temperature at night, by as much as 10° C. This slows down all body processes and energy costs. Chickadees do this. Yet they will lose 10 % of their weight nightly (web.stanford.edu).

Our birdbath is made of a plastic composite; it won't crack if the water freezes. It contains built-in electric coils to prevent freezing. It sits atop a large planter, plugged into an outdoor outlet on our deck.

It might not be obvious to flyby birds, but once found by birds it is very busy. Traffic begets traffic. Oh, and it's handy for filling, which is very important to both the birds and me.

Also important — never add anything to the water intended to prevent freezing. It's best to not add anything, period.

For more information google "heated water for birds in winter." I got 39 million results.

Lifelong birder Jim Williams can be reached at woodduck38@gmail.com.

Avoiding birdcicles

Most birds will not bathe when it is very cold. If, however, the idea of creating birdcicles concerns you, simply place a half dozen sticks across the water, spanning the pool edge to edge. That should discourage risky behavior.