Baby it’s cold outside…
For most animals, the winter is all about survival. It’s a time when days are short and food is at a premium. But this isn’t true for every species. Two of the Park’s signature predators have other things on their mind at this time of year. Both our largest owl species, the barred owl and the great horned owl, are actually beginning preparations for breeding during the depths of winter.
The barred owl is the most common owl species in the Park. Its ‘who cooks for you’ call is one of the most distinctive sounds of the forest in spring and summer. Barred owls pair for life and normally nest in a tree cavity or an old nest of another bird. They begin courtship and nest preparations in the depths of winter and the female normally lays eggs in February or early March, although in the southern United States, barred owls often begin breeding even earlier.
The great horned owl is even larger and one of the Park’s top predators. They are remarkably adaptable and range right across the Americas from Argentina to Alaska. Living in such a wide range of habitats means changing nesting behaviour. Their nest is normally in a mature tree, but they will also choose cliff sides, buildings and in certain areas even nest on the ground. Like the barred owl they begin breeding during winter and incubate eggs during February and March, even in the colder parts of their range like Eastern Canada. Only in extreme north does laying take place in late March and April, although this is still much earlier than other breeding birds.
So why do owls choose to nest early in the year? Like most decisions in biology it’s about getting a leg up on the competition. As a large species, their chicks take longer to develop than small songbirds. A horned owl chick spends more than forty days in the nest after hatching, compared to 16-18 days for a young kinglet. So, by starting nesting early, owls are able to fledge their young in spring which enables the growing chicks to learn the hunting skills during a period in the year when food is abundant. Timing is everything!
By Ben Hill, Communications Volunteer