Station reports

Raptors are cool, and I am not talking about the prehistoric ones made famous by Jurassic Park (although they are plenty cool), but rather the modern day ones – the birds of prey. September is a great month for raptors in many ways: it is the start of saw-whet owl banding, it is the peak of sharp-shinned hawk and northern harrier migration and the start of buteo (the soaring hawks) migration. Most of the year we don’t see buteos, but in the second half of fall migration we are treated to red-tailed hawks, rough-legged hawks, and broad-winged hawks passing overhead. The diversity of raptor species is probably one of the things I appreciate most about them. They vary greatly in size, hunting techniques, colouration and what time of day they are active. From the falcons that rely on pure speed to out-fly their prey in the open sky to the northern goshawk and sharp-shinned hawk that use their long tails and short wings to out-maneuver songbirds in thick forest. The red-tailed hawk uses extreme telescopic vision to see mice from high in the sky whereas northern harrier and most owl species rely almost entirely on sound to track down prey. There is the osprey that hovers over the lake to dive-bomb fish and the kestrel that hovers over ditches looking for grasshoppers and mice. The bald eagle has a wingspan of 2 metres compared to the northern pygmy owl’s scant 30 cm. To be able to do what they do so well, raptors have some really neat adaptations. It would take me the entire newspaper to discuss all the various features that make each species of raptor special so I will just talk about the sharp-shinned hawk. Aside from the northern saw-whet owl which we have a dedicated monitoring program for, the sharp-shinned hawk is the only raptor we catch regularly. We catch a few in the spring, but fall is when they consistently hit the nets; we band 20-30 of them during late August and early September. Sharp-shinned hawks are highly migratory and if you have a bird feeder you have likely seen one lurking around it at some point during the spring or fall. The young individuals are streaky brown with a yellow eye and the adults are streaky on the breast and slate blue on the back with deep red eyes. Sharpies, as we affectionately call them, are the masters of hunting songbirds. They will perch in the forest and watch for other birds moving through the trees; their short wings allow for rapid acceleration and their long tail acts like a rudder helping them to weave through the branches. Their long legs give them incredible reach and their long toes are tipped in deadly recurved talons that lock into their victims. Sharpies have another adaptation that helps to further increase their maneuverability – they have a pronounced alula. The alula is a tiny bone that is essential a bird’s thumb, it has three feathers attached to it. For most birds the alula is barely noticeable on the leading edge of their wing, but for sharpies it is long and protrudes out. When it is flared it actually resembles an extra little wing. And what is not cool about a bird that practically has four wings?