There are only three species of eagle breeding in the Algarve, the migratory, buzzard-sized Booted, the resident, larger Bonelli’s and the Short-toed, which is mainly a summer visitor, although a few overwinter. It occurs throughout Portugal except for the extreme north-west. A large bird of prey with pale underparts, hovering at moderate altitude over dry ground, is certain to be Short-toed. (Ospreys sometimes hover over water.) Its excellent eyesight picks up the slightest movement below and, while it will take any smallish prey on offer, it specialises in catching snakes and lizards, hence the short claws to grip its wriggly catch tightly.
The rather broad, long wings, which have evolved for efficient soaring and hovering, give a false impression of size as it is quite a lightweight compared to some of the larger eagles. The large, owl-like head and the dense breast feathering, affording protection against snakebite, add to the illusion when perched. It nests in woodland with access to open areas for hunting, so the terrain in the southern hinterland suits it perfectly.
Most birds arrive from sub-Saharan Africa in March. This year my local pair arrived back together on the 10th. Although the species has declined in much of Europe during the last century, mainly as a result of habitat loss, the Portuguese population seems quite stable, with the main threats being electrocution (pylons provide excellent vantage points) and wind farm turbines.
Short-toed Eagles are monogamous with the pair bond often maintained over successive years. The displays of the male are less elaborate than in many birds of prey but ‘sky-dancing’ with slow wingbeats and undulations can be performed by either sex. Males sometimes carry a snake in their bill during these manoeuvres which can be dropped and re-captured in mid-air. It may then be presented to the lucky female!
Most large birds of prey are not very vocal, but the Short-toed Eagle is an exception. Calls vary from a melodious fluting by the male to less musical whistles by both sexes at the eyrie. A displaying male has been recorded uttering a well-defined ‘ooee’ twelve times in three descending steps. More threatening noises are made if another bird of prey enters the territory. I have witnessed my local pair determinedly ‘seeing off’ intruding Bonelli’s Eagles.