pond ... bird watering question

[rossb]

I'm not sure if anybody else maintains a water source for outdoor birds but if you do...I have a question. This year I just started putting a small heater in my pond for a watering hole for the birds (we feed them all winter). It leaves an area about 2 square feet open. I have noticed that the water seems to really evaporate or sublimate quickly. In fact the area dries up evey 3-4 days, which is about 10-15 gallons. Does this seem normal?

[Delphinus]

Seems totally normal to me. If we get 10% humidity in these parts we call it "rain." :D It's not going to take a long time at all to lose heated/open surface water like that. Indoors, I lose 4-5 gallons per TANK per day in a house maintained at >60% humidity, so 15 gallons in 3 days, outdorrs and heated, at this time of year .... I'm not surprised at all by that kind of rate. In fact I bet the loss could be a lot higher than that if there was a lot of localized air movement over the water surface...

Just take a look at the trees around Banff Springs on a day below -15C .... that's a lot of water ripped out of that pool.