The underlying assumption is that undertaking this task is worthwhile because by finding and then trying to protect the breeding habitat of wildife such as hawks that require relatively large areas to survive, other wildlife that depend on the same general habitat (e.g., area-sensitive birds, mammals, and herptiles) can also benefit from such protection efforts.

The following guidelines are intended to help anyone trying to find and identify hawk nests and nesting habitat.

  • Familiarize yourself with the birds and their nesting habitat requirements by reading about their natural history and biology and by consulting bird guides. Excellent sources include:
    • Peck, G.K. and R.D. James.1983. Breeding birds of Ontario. Nidiology and distribution. Volume 1: Nonpasserines. Royal Ontario Life Sciences Miscellaneous Publication.
    • Headstrom, R. 1961. Birds’nests: a field guide. Ives Washburn Inc.
    • Szuba, K. and B. Naylor. 1998. Forest Raptors and their nests in central Ontario. A guide to stick nests and their users. Southcentral Section Field Guide FG-03, OMNR, North Bay. 75 p.
  • Hawks will sometimes build or repair more than one nest within their nesting territory, but will only use one of them in any given year. This is particularly true for Red-shouldered Hawks and Northern Goshawks. Such nests are usually with 200 metres of each other.
  • Signs of active nests include: down feathers stuck to the nest twigs and sticks, molted feathers near or under the nest tree, freshly broken ends on twigs used to build the nest. Northern Goshawks, Red-tailed Hawks, and Red-shouldered Hawks decorate their active nests with vegetation, often sprigs of conifer foliage, especially hemlock. Little decoration is usually seen on Cooper’s, Sharp-shinned, and Broad-winged hawk nests. Active nests may also show some whitewash on the foliage of the nest tree and nearby trees and shrubs. Accumulations of feathers; regurgitated pellets of bits of bone, fur and/or feathers; as well as prey remains may also be found near the nest.
  • Frequently the tail of the hawk (usually one of the accipiters) projects over the nest edge and is all that is visible to the observer on the ground.
  • Use tape-recorded calls sparingly and watch for silent hawks (usually accipiters). Red-shouldered Hawks will call almost incessantly as they approach a tape-recorded call. Try to follow or retrace the flight path of hawks if they come to the tape.
  • In March and April, investigate any calls just before dawn, that sound like pileated woodpeckers. They may be a pair of courting accipiters.
  • Investigate what crows are mobbing (strong, incessant “cawing” by numerous birds). It could be an owl or one of these hawks.

If nests are found that appear active but no hawk is present, suspect a Cooper’s Hawk nest. Sit hidden and quietly and use the back of your hand or predator call to produce a squeaking sound. These hawks may respond by flying into view long enough for an identification to be made.

Nestsfootnote 1

Sharp-shinned Hawk nests are usually well-hidden high in the foliage of conifer trees, especially spruce, in young to medium age forests. Dense groves of spruce are the preferred habitat.

Cooper’s Hawk prefer to nest in deciduous trees (mainly beech and maple), but will also nest in the lower crown of white and red pines and hemlock. They often build their nests in pine plantations that are 30 years and older which are adjacent to mature deciduous forest. They may resemble crow nests, but will not have grass in the nest as do crow nests. These hawks are shy and will usually slip off the nest unnoticed.

Northern Goshawks are most commonly found in large, dense stands of mature or old growth forests, and will also use older pine plantations. They nest in both deciduous and coniferous trees. In conifers, the nest is close to the trunk and made of longer, thicker sticks than a Cooper’s Hawk nest. Most nests are in conifers (red, white or jack pine), poplar, and yellow birch. Nests are often close to a clearing that provides a natural flight path nearby (an old creek bed, woodland road, break in the canopy). This species is very aggressive and likely to attack humans that are in the vicinity of the nest.

Broad-winged Hawk nests are usually found in dense forest and appear loose, and poorly built. They prefer to nest in yellow and white birch in denser, younger forests. They rarely nest in beech trees, and occasionally nest in pine plantations. They may decorate their nests with sprigs of green deciduous leaves.

Red-shouldered Hawks primarily in beech trees, followed by maple trees. Nest trees are usually large and tall. Their preferred nesting habitat appears to be mature, closed-canopy stands of maple-beech, with few saplings in the understory. The canopy often looks like an umbrella over the nest. This hawk shows the strongest preference for nesting near (equal or less than 250 metres) water, especially small woodland ponds and creeks. This hawk now appears to nest mainly in large forest tracts of 200 ha or more, especially in areas where there are many Red-tailed Hawks. This hawk shows strong site fidelity (20 years or more) and is strongly territorial and very vocal during the breeding season.

Red-tailed Hawks build large nests high in a variety of trees and often reuse the same nest. They also decorate their nests, usually with fresh conifer foliage. Nests of this hawk are usually found near forest edges; in small, isolated woodlots; and in fence rows. They may also nest on hydro towers. They readily respond to recorded calls of Red-shouldered Hawks.

Merlins prefer to nest in old crow nests built near the top of spruce trees. They often nest near lake shores. They are very protective of the nest and will fly 500 metres or more to harrass other birds.

Footnotes