From the time mum is on the eggs to the time when the juveniles fledge and are capable of hunting for themselves, it is dad’s job to hunt for the entire family. When dad returns to the nest site with food, he can pass the food on to mum or the juveniles in one of two ways: an aerial foodpass (done in mid-air) or a food transfer (done on the ground or on a branch).
This series of images shows a food transfer between mum and dad on a branch.
Image 1: Dad (on the right) comes in with food in his talons as mum walks towards him and tries to pry the food out of his talons. While dad comes back with food for the family, he is quite loathe to give up what is in his talons (guessing instinct kicks in which dictates that you do not share your hard won prize) and mum literally has to pull it out of his talons. In this case mum was unsuccessful in getting it out of his talons and he flies to another branch, food still firmly grasped in his talons.
Image 2: After flying off to another perch, dad transfers the food from his talons to his beak all the while keeping an eye on mum.
Image 3: Still with food in beak, dad contemplates his options – does he stash the food away, does he go into the nest and feed the chicks himself or does he transfer the food to mum?
Image 4: Finally dad decides to transfer the food over to mum and looks up towards her – mum all the while has been sitting on a branch above dad constantly whining and vocalising and keeping an eye on dad.
Image 5: Dad flies up to mum and prepares to transfer the food to her.
Image 6: The actual food transfer takes place from dad’s beak to mum’s.
Image 7: The food transfer is now complete. Notice how mum’s posture has changed – she’s fluffed herself up to make herself look big and mean and she’s brought one wing forward so as to try and cover the food. This posture is called ‘mantling’.
Image 8: Mum flies off to another perch, food in tow and vocalises for a while usually until dad flies off to either have himself a rest or go on his next hunt.
Image 9: Once dad has left the scene, mum starts investigating the food in her talons to try and figure out what’s for dinner. Usually she would have a bit of it herself to satiate her own hunger considering she does very little / no hunting for most part of the nesting period.
Image 10: Once mum has had a bit, she transfers the food to her beak and prepares to take the food to her eagerly waiting chicks who have seen this entire episode unfold as food transfers happen in close proximity to the nest.