About the Nest
Two Red-tailed Hawks built a nest on a window ledge at The Franklin Institute in Philadelphia. The nest sits just outside a window where a camera has been positioned to create this video stream. The camera looks through the glass window pane which is 24 inches wide (~61 cm). No artificial lighting has been added, so the nest is only visible during daylight hours.
About the Hawks
The Red-tailed Hawk (Buteo jamaicensis) is the most common hawk in North America. It is a large bird with a broad, red tail. The female is usually larger than the male. Red-tailed Hawks are monogamous, meaning that a hawk will choose one mate and stay with that mate for life.
Philadelphia provides a suitable year-round habitat for Red-tailed Hawks. They can be found in open areas with elevated perches where they sit and watch for their prey. They are meat-eaters and feed on small to medium-sized mammals and birds. In an urban area such as Philadelphia, that would certainly include rodents, although these particular hawks are most commonly observed to be feeding on pigeons.
The Red-tailed Hawk builds its nest in a tall tree or other elevated perch. The nest is a circular assembly of sticks and twigs, lined with softer pieces. It appears that The Franklin Institute's hawks have used newspaper scraps and feathers to soften their nest. Tree bark and leaves are also known to be used in nesting.
Red-tailed Hawks will lay a clutch of two to four eggs in March or April, depending on climate. (A clutch is the collection of eggs, kind of like a "litter" in other species.) For Philadelphia's latitude, the eggs are likely to be laid in mid-March.
The female lays the eggs one at a time, approximately every other day. The number of eggs is related to the availability of food in the area, as a well-fed female is likely to lay more eggs.