We are moving into the season where our species diversity increases remarkably, as friends old and new return from places distant to establish their summer homes, raise families, and feed heavily on the bounty before leaving again during the fall. Temperatures warm, birds of all shapes and sizes flood in on gentle southern breezes, and insects emerge from their winter diapause. This is the favorite time of year for many birders and naturalists alike. But do you know what some of your favorite raptors spent the winter doing?
The answer varies quite a bit with the species - with some staying here for the entire winter, others travelling only as far south as they needed to (some only to the Southern part of Maine!), and yet others winging it as far as South America and eastern Peru, Bolivia, and southern Brazil. The Red-tailed Hawk shown in the first 3 images is one of the few species that "leap frog" during migration, where northern populations sometimes winter further south than southern populations. Most Red-tailed Hawks would be considered moderate distance migrants, with only about 90% of the population moving in the fall, and travelling less than 500km. Many Red-tailed Hawks can be seen along the interstate in southern Maine over the winter months.
On the other hand, the feisty Sharp-shinned Hawk dreaded at bird feeders by all birds Blue Jay sized and smaller will be returning from the southern part of the Continental United States, or from as far away as from Central South America. These secretive forest birds are often best seen during southward migration when they are very concentrated in numbers, but they are much more dispersed when returning on the northbound trip. They will be looking for low and mid-elevation conifer stands to breed and continue to create nightmares for small songbirds and rodents.
Bald Eagles demonstrate a very complex migration pattern which varies with location and age. Many northern Bald Eagles will over-winter south of their breeding grounds, while others will move towards a coastal area where conditions are more temperate and fish remain available. Yet others will remain near their nests. Birds that remain near their nests are able to begin the nesting process remarkably early -- in fact, mating has already begun for these raptors! It is easier to get an early start when you didn't have to travel far.
Northern Harriers can be found year round in Maine, particularly in coastal areas. These birds are considered to be moderate to long-distance migrants, and are willing to move under a variety of poor conditions including inclement weather, wind still conditions, and even at night. They will be returning to open wetlands and grasslands with thick vegetation to nest.
Ospreys are willing to migrate very long distances and will even cross large stretches of open water, something that many birds of prey are unable to do. They have been seen to be "packing along lunch" during migration, carrying fish to be eaten later along the route. The timing of the return of these charismatic birds coincides with the migration of the Alewives, which provide a valuable food source for restocking calories drained during the long trip. Many hours can be spent watching ospreys hover and dive for dinner - and sometimes, a lucky bird will emerge with multiple fish hooked in their sharp talons!
The falcons of our state are fierce little birds - fast, petite, and deadly, to be feared even by birds on the wing. Merlins can migrate very long distances, even crossing open water. They will typically use powered flight, meaning they don't commonly take advantage of thermals even if available, but use their powerful wings to propel them for much of the migration. Many of these birds will spend their winter basking in the sun of the southern United States, but some will travel as far as Ecuador, so don't be too surprised if the first Merlin you see this year looks unusually sun-tanned!
As you start to see your favorite birds returning this spring, take a moment and ponder what they have been doing since the fall - and where they have been. The answers might astound you! The migration feats demonstrated by some of these small animals is truly incredible.
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