As a fully migratory species they arrive here in France from their winter quarters in West Africa from March until May, departing again from the end of August through September. Favourable habitat is extremely important for them with an abundance of snakes within a reasonable hunting range, especially when nesting. Generally a patchwork habitat is preferred of woodlands interspersed with dry open spaces, scrub and to some extent agricultural areas. Large trees or more rarely cliff faces are required for nesting and close proximity to human activity or any other disturbances are avoided.
Short toed eagles mainly hunt by soaring, frequently at great height where they can also hover for short periods, then, when prey is located, it will usually be taken following a long, direct shallow glide with head slightly tucked back between wings with “elbows forward”.
In France, snakes make up 71 to 96% of their diet. Non snake prey is mainly lizards, including slow worms when weather is bad and some 5% of their prey are not reptiles but small mammals - voles, mice and even hedgehogs. Exceptionally frogs, toads and mantis will be consumed. There is no preference for any type of snake and although they are not immune to vipers’ venom they have no difficulty catching and killing them, indeed in some regions the Asp viper can make up 25% of their regime. Potential lifespan is 30 years in the wild with 18 years being average.
Short toed eagle
Left a great little video of young Short toed eagle in the nest.
Photo right shows a typical view of a Short toed eagle.
Due to a dependence on snakes as a primary food source the Short toed eagle is restricted to the southern and eastern regions of Europe with the largest populations to be found in Spain and France.
They also occur in other countries along the Mediterranean such as Italy, Greece and Turkey. In Eastern Europe they can be found further north as far as Belarus and occasionally but very rarely in the Baltic States.
Outside of Europe they are found eastwards to Kazakhstan and south to Iran.
All of these are migratory summer visitors although there is a sedentary population on the Indian Subcontinent. There are no subspecies and the closest relatives are the Beaudouin's Snake Eagle Circaetus beaudouini and the Black-breasted Snake Eagle Circaetus pectoralis, both are African species that were once considered to be subspecies of the Short-toed Eagle, but are now considered to be completely different species.
Short toed eagle nests are invariably constructed high in tall tree in a secluded area,, (rarely a cliff ledge may be used). The nest, which is made from twigs about the width of pencils and lined with green leaves or pine needles, is relatively small and light for a bird of this size. These small nests are almost invisible from the ground, as they are carefully hidden at the top of the tree in a branch junction facing south / southwest and away from the wind. Their height varies from 6 to 30 meters and the same nest will be restored and used year after year.
The female lays one plain white egg which is incubated for 45-47 days and after hatching, the young eagle stays in the nest for 60-80 days where it is feed with pieces of snake that are provided to the female by the male. As with many raptors the male is not allowed near the chick although he will remain in close proximity to the nest when not hunting. Only after two months and with enormous effort is the young eagle able to swallow larger snakes without assistance.
The young eagle finally leaves the nest at around 70 days when it learns to hunt with the male whilst also being provided with food by both parents. For a brief period in August and September all three birds can be seen flying, soaring and playing together before they begin their journey to West Africa. Here the juvenile eagles tend spend the first few years of their lives before one spring they make the journey north to seek a mate.
Major threats and menaces are easy to identify.
Here in both France and the rest of Europe illegal shooting, electrocution from overhead distribution lines and a reduction in the numbers of available prey have been, and continue to be, a cause for concern.
Disruption to habitat, cutting of large trees with other forestry work during the periods they are here and reduction in suitable hunting zones.
A growing concern is the increasing number of wind generators being built and the impact they are having on this and other species, something that the “powers that be” keep playing down.
Outside of Europe in their winter and transit zones illegal hunting is an important issue.
It should be made clear that a breeding couple raising one chick will require 850 to 1250 snakes during the period April / September, therefore conserving a good snake population is fundamental to their continued presence in France.
Currently the situation in France is stable, if anything a small increase but much may depend on the weather providing the right conditions for breeding. Many raptors will not breed if there isn't enough available food for feeding young.
Map Source - Rapaces nicheurs de France ISBN 2-603-01313-0
Photo - Short toed eagle killed by wind farm in Spain.