Video of the ringing in Uccle
The two younglings of Uccle were ringed yesterday (video 1). Their weight, relative to their wingspan makes it possible to determine that they are both males. Another way to conclude that they are male, is that they are much thinner than females. Female Peregrines are much bigger than males and are able to catch large prey such as ducks or even wild geese. Evidently, males would be unable to transport this type of prey back to their nest, since it is impossible for a male Peregrine to carry a mallard of a kg or a greater white-fronted goose of 2.5 kg!
The ringing itself takes a few minutes per falcon. It is paramount to be as efficient and fast as possible in putting the chicks back into their nest; preferably without any delay. Falcon parents, like all bird parents, do not recognize their younglings’ scent. Therefore, handling by humans is not a problem, unlike with mammalian parents such as rabbits, hares or deer, where the risk of abandonment of a youngling is very real from the moment it is touched by humans.
However, this does not mean that Pilgrim parents are indifferent to the operation! When they realize that you are approaching their offspring, they react vehemently. The female takes on the main role, probably not as a result of a particularly developed maternal instinct, but rather, again, because she is much stronger than her male counterpart and therefore more likely to repel what she considers "the attack of a predator". She attacks the intruder, most of the time without hesitation. If the intruder is clearly visible, she will swoop down towards him, closing in up to a few meters, and even, in the most exceptional cases, will go up to graze him. The male does not swoop down. He stays at a distance but screams with all his might to intimidate the intruder. If the intruder is not completely visible, the falcon can be even more aggressive and attack with her claws first. This is not the case for all Peregrines. Some are (much) more protective than others. This is certainly the case with the female nesting in Uccle since (at least) the spring of 2016! She doesn’t seem to be afraid of anything. As soon as we slide the little door that allows access to the nest to adjust the camera or, when the time comes, to get the falcons to ring them, this female Peregrine rushes in. Her attack is impressive. She plants her powerful claws in the hand that advances towards the falcons, without hesitation! The obvious way to avoid being hurt is to wait until she is absent. But a female Peregrine rarely leaves her hatchlings. At their slightest cry, she returns to the nest to check that everything is going well. And, if necessary, to put the potential predator out !
These behaviours show that Peregrine Falcons are exceptional parents. Their attachment to their younglings and the energy they put in their defence explains why the cases of predation and mortality among nestlings are very exceptional.
The couple of Uccle Peregrines have been nesting in the bell tower of Saint Job Church since 2015. Until now, they have raised 4 falcons each spring. In 2015, the brood had 1 female and 3 males, in 2016 it was exactly the opposite with 3 females and 1 male. Last spring, a perfect balance with 2 females and 2 males.