Date: 3/13/25 3:09 am From: 'PAUL ROBERTS' via Arlington Birds <arlingtonbirds...> Subject: Re: [Arlington Birds] Red-Tails in love and war
Good questions, Nina. Red-tailed Hawks are courting now. Urban males are seeking to (re-)establish a nesting territory (and nest), reaffirm pair bonds or attract a new female. Often an existing pair may have several nests or proto-nests; (partially built but previously unoccupied nests that they have built for multiple reasons, including using them as indicators the territory is already occupied, or alternatives should the nest used previously have been occupied by a Great Horned Owl or blown down in a storm.) Great Horned Owls, for example, are the earliest nesters, but usually don't build their nests or do much maintenance. Every year they appropriate nests built by other birds, often Red-tailed Hawks. A pair of Red-taileds that nested in Mt. Pleasant Cemetery for years lost their nest to a pair of "newly-wed Bald Eagles that took over their nest, "clear cut" the branches around it, and built an enormous nest in its place, before the Redails began laying eggs. In early spring Redtails need to improve or touch up any nests they've built to show current, active ownership. Then they must establish or re-establish the boundaries of the nesting territory they will maintain, and the more expansive critical hunting territory they will defend. They typically do this by aerial displays that include threats and intimidation but rarely actual fighting, which is very risky for both parties. There are hard boundaries and soft ones, and if there is a neighboring male/pair, they have to re-establlish those every year. That is usually done through soaring displays and vocalizations, including tail chases, and dropping talons, but rarely any actual combat. Talon locking in raptors is now believed to be agonistic behavior that has little or nothing to do with actual romance or courtship of another gender. Courting birds, especially males, wills seek to "sky dance" with the female, to "duet" with her, by mirroring her movements much like in pairs figure-skating, or the male will attempt impressive dives to show his physical abilities. Locking talons is "nuclear war," when bluffs and intimidation don't work. Over a decade ago two Redtails locked talons over the Mystic Lakes, crashed to the trail, and one male dispatched the other. (We removed and buried the carcass.) When a male does successfully defend his territory/nest/mate early in the spring, he is often "rewarded" with an opportunity to copulate with her. One pair on the Mystic Lakes had built seven nests or proto-nests. A heavy early April snowstorm brought down the largest nest they had used successfully the year before, as well as two proto-nests. They ultimately nested successfully in an eighth nest I had not discovered (could not actually see) when the foliage emerged. Pairs of urban Redtails in Massachusetts don't tend to migrate and generally keep close to their nesting territory. Thus the 3 or more you might see soaring together likely includes a new bird seeking a mate, or working to establish boundaries for a territory it is attempting to delineate. Note that most Redtails do not nest and breed until they are four years old and there can be intense competition for good nesting territories, which means challenging owners of territory already occupied. Most disputes are settled without physical contact. Best, Paul Paul M. Roberts Medford, MA <phawk254...>
