Juvie dispersal: voluntary and forced

[Donna]

Great piece by C & C

At most of our sites the juveniles have gotten to the point where they are either hunting independently and have dispersed from their natal nest sites or are present at the sites only sporadically for some supplementation from their parents. Through our observations we’ve seen voluntary dispersals: when the juvie is ready for independence and leaves the site on his/her own. In this case, we’ve occasionally seen adults flying around calling with prey, apparently looking for a juvie to deliver prey to with no takers. One standard belief about peregrines is that the parents will continue to feed their young as long as the young seek food from them, and some of our observations fit this scenario. Another theory is that if juvies overstay their welcome at their natal nest site, their parents will withhold feeding and then become increasingly aggressive in encouraging their young to leave the territory, even going into attack mode when necessary. We’ve experienced this as well, at one point seeing Rocky send one of his juvies away from the CVNP site shrieking as the juvie returned into the fall and food-begged with a full crop. So it seems that juvie dispersal is both voluntary and sometimes forced by the parents… the juvie’s drive for independence coincides with the adult’s intolerance for sharing their territory on a long-term basis.

Leading up to their dispersal, the juvies develop the necessary survival skills partly by practicing on their parents. So, it makes sense that the juvies become more and more aggressive in seeking food, and the adults avoid them by hiding and then retaliate when they’ve had enough as one of their departing lessons. The pics from this sequence are a bit outdated, but they show juvies from the Hilliard site knocking adults from their perches: one of the males chasing Titan off a branch perch, and the female juvie, Brazen knocking GG off the fence and then chasing after her…

[MAK]

Thanks for sharing Donna!