I live in Massachusetts, United States. A large number of backyard birds overwinter in our yard. Some of the smaller varieties include American Goldfinch, American Tree Sparrows, European Starlings. The larger ones include Northern Cardinals and Mourning Doves.
Many have been here all year, and are accustomed to our landscape. They know where our feeders and bird baths are located, and that we keep them stocked with fresh food and water. Beginning in November, and lasting for months, the water in the bird baths freezes. We bang out the ice, then clean and fill them with fresh water. That works for a while, but by the depth of winter, the water freezes more quickly than we can keep up with it. We keep some small saucers close to the house, which are easy enough to handle, but our full-size feeders are a distance away, larger, and harder to maintain. (I admit I'm not always in the mood to trudge out a few times a day to break the ice!)
This year we're considering buying a few submersible water heaters. (I've seen them called both heaters and de-icers. I'm not sure what the difference is, or if it's an important thing to know.) They're designed to go into an existing birdbath. They come with cords which plug in, and have thermostats which keep the water from freezing.
They come in many different sizes, shapes, types of materials, thermostat ranges, lengths and widths of cord, wattage levels. Some are round, others flat. I've heard of one that has timers which turn on during the times of day when birds are more likely to be active. I think those are designed to save the cost of electricity, but they're more expensive to buy, so it probably balances out in the end! We don't need something like that. I've also seen free-standing heated bird baths, but we're not interested in adding to our collection.
Some of our feeders are plastic, others are ceramic and concrete. The diameters vary, from approximately 17 inches to 25 inches. None are deeper than 3 inches at the deepest part, as that's the maximum depth recommended for small birds.
Here are the most important criteria:
- Dependable, accurate thermostat
- Water kept at or above 35°F (1.7°C)
- Effective to -20°F (-28°C)
- Long-lasting, warranteed for at least a few years
- Durable, won't break under the weight of snow and ice, or while being handled
- Strong, safe cord, with no risk of short-circuit or electrical fire
- Cool surface, with no danger of burning birds and backyard animals when touched
- Easy to clean in case of dirt, mud or algae buildup
- Easily removable for cleaning the bird bath
- Either usable in both plastic and ceramic bird baths, or clearly marked for the specific application
We'd like to stay in a mid-range price category. I'm not asking how much to spend, just to keep in mind when recommending something that we don't want to sacrifice quality and features just to save a few dollars, but we also don't want to spend top dollar to get fancy features we don't need.
I'm also not asking for brand recommendations, but would welcome any from people with experience.