Wednesday, April 30, 2014

Q & A with John Blakeman

Pale Male, Octavia [his mate] and one of their 2 chicks in the nest on Monday 4-28-14
photo courtesy of

 Reader  Katy Salter Goodell sent in a question about Red-tailed Hawks that I forwarded to Ohio hawk expert John Blakeman. Here is the question and his reply:
I have a question about the sibling pecking among red-tailed hawk hatchlings that lasts for ten days to two weeks. It sure looks--at first--like aggression, since the hatchlings peck at each other rather than at twigs, unhatched egg, etc.  BUT it doesn’t seem correlated with conflict over food or establishment of dominance. And then it disappears.
Is there any scholarly research on this pecking?  Any interesting comparisons with other species?
(I know that sibling pecking has been studied in grebes, where it definitely is associated with access to food, and would be defined as aggression. But red-tails don’t fit that model) 
Katy Salter Goodell

             John Blakeman replies :

Although these behaviors of young Red-tailed Hawk eyasses can be labeled "sibling pecking," they are not. Hawks do not, and cannot "peck," that is, that they cannot thrust their bills into food or other objects.
Hawks, even as young hatched eyasses, can only bite. Their curved-over bills aren't made for pecking. They can only bite, not peck. The muscles controlling biting motions in the jaw are extremely week. The little hawks can barely open their bills, and their ability to grip down tightly when biting is very limited.
Hence, there is never any injury when Red-tail eyasses so typically spend lengthy periods "biting" each other. Mostly, they are just pushing their bills against each other, and also learning how to truly bite and grip --- without injury to the sibling. All of this hones head and neck motion controls. Essential.
These behaviors and neuromuscular reflexes are exactly the same as used when plucking tidbits of food from the mother's food-garnished bill during feeding. At this young age, the neurological pathways and circuits of the tiny hawk are very limited. Every behavior is a "going through the motions" reflex. Rather indistinct and repetitive.
But in the second week, behaviors become more varied, deliberate, and controlled, as the brain begins to mature.
--John Blakeman