It’s minus 15 degrees Celsius in January, and you hear a woodpecker drumming, a behaviour usually reserved for courtship and marking territory. It is still far from spring, and the time for laying eggs. The lengthening of daylight is the main factor triggering the hormonal changes necessary for reproduction in birds. That is why woodpeckers might make sporadic territorial gestures in the middle of winter. With even longer days in the spring, together with warmer temperatures and more abundant food sources, the nesting behaviour of most birds intensifies.
Nonetheless, here in Nova Scotia, there are a few bird species whose nesting activities are well underway before the end of the winter. One of the most noticeable is the Common Raven. Ravens can be seen doing their aerial acrobatics, diving and rolling, in February as part of their courtship rituals. By early March, ravens are constructing a nest or repairing the one from last year. Keep a look-out for birds flying with a large branch in their beak for nest building. Ravens can be distinguished from crows by their larger size, wedge-shaped rather than rounded tails, and croaking rather than “cawing” calls.
Owls also tend to be early nesters. Our largest owl and earliest nester is the Great Horned Owl. You can hear it now, especially on a calm, moonlit, night. The male’s territorial “advertising” call is a deep-toned “who-hoo-ho-oo” that can be heard at a great distance despite its low volume. In the first week of March, the female starts to lay her eggs.
Our most common owl, the Barred Owl, nests somewhat later. In contrast, to its larger cousin, this owl has a booming call that reverberates throughout the forest with its “who cooks for you!”. The Barred Owl lays its first eggs near the end of March. The small Northern Saw-whet Owl does not start laying eggs until April, but you might hear the male’s advertising call, a long monotonous series of single notes, in early March.
The most famous winter nester is the iconic Canada Jay. A bird of the boreal forest, the Canada Jay has been documented incubating its eggs in minus 30-degree Celsius temperatures. Nest building can begin as early as late February, and here in Nova Scotia, at the southern limit of its range, nests are generally built by mid-March.
Why does the Canada Jay nest so early, when food is scarce, and the weather is so unfavourable? It is not clear, but scientists believe that it is related to the Canada Jay’s primary survival strategy. That strategy is the storage of food to get them through the winter. Each bird stores thousands of food items each summer, covering the food in its sticky saliva, and hiding them in bark crevices, under leaves or lichens. Months later, during the winter, the bird remembers where all these thousands of items are hidden and recovers them to eat. Thus, it is thought that the birds nest early so that they have sufficient time to store all the items they will need to get through a harsh winter environment.
However, climate change puts the Canada Jay at risk because the frequent thawing temperatures now experienced during the winter months leads to the spoilage of its food caches, sometimes leaving the birds without enough food reserves to survive the winter. This is especially true in the southern part of its range, like in Nova Scotia.
All the early nesting birds I have discussed so far, have spent the winter locally. But soon there will be another bird that will arrive from its wintering range in the southern United States. This is the American Woodcock. Soon after its arrival in early March and onwards, the male woodcock begins its distinctive aerial displays, sometimes described as a “sky dance” to attract a female.
It starts with the male woodcock making a “peent” sound while standing on a bare spot of ground. He rotates so his “peent” can be heard in all directions. When he takes off, the bird spirals upward to a great height, making a rapid twittering noise that sounds vocal but is in fact a mechanical sound produced by the air passing through its flight feathers. For the finale, the bird drops from his great height making a bubbly chirping vocal sound until it lands and utters what sounds like a proud “peent” of success. To witness this amazing display, head out at dusk to an old field and listen for the “peent.”