Out of rehab......

We have had an unusual turn of events on one nest that I have been watching. The adult male was injured in early July and wound up in rehab at The Raptor Center. That left the female caring for three chicks on her own. When he was ready for release, they asked if I would like to return him to his nest.

In 22 years of studying these birds, I have never had the opportunity to release an adult osprey back into his territory. We have rescued and returned many juveniles in those years , but not that many adult Ospreys get injured and recover fully during the breeding season so this was something new for me. Another chance to learn! We pondered what might happen after a full month in rehab. Would his parental instincts have turned off? We expected that the female would recognize him, since they had been together for several years and mated pairs seem to know each other upon return each spring. When I released him however, the female went after him like a bat out of hell. Full on alarm calls, way past the usual chirping that is an indication of an intruder. She dive bombed, and chased him relentlessly. I stayed all day to observe and she would not let him anywhere near the nest. The chicks all had empty crops. She finally responded to her chicks cries for food and left for a short time, during which time the male calmly perched near one of his fledged offspring. When she returned with a fish, she chased him off again. The next day a male flew over with a fish and, again, she took off after him. We watched closely for days and did not see the male here. Six days after his release, I arrived to check on the situation (a volunteer monitor had been checking the nest almost daily) and I found all chicks there food begging, one eating a fish and the male calmly perched nearby.  Oh happy day! BUT, then the female returned and chased him off again. This is all very interesting to me behaviorally. We have to be careful about  anthropomorphizing in a situation like this, and it's easy to slip into that mode for some easy answers. One way I evaluate behaviors is to realize that these birds are largely driven by two motivating factors. One is to survive and the other is to reproduce. Both of these Ospreys had been deeply involved in those struggles. The male struggling to survive in a difficult situation (rehab is not easy for an osprey) and the female struggling to survive herself and to make sure that her offspring survived. Did she not recognize him? Did she determine that this male was unable to provide for her and the chicks, and therefore saw him as a threat? Does the pair bond dissolve under these kinds of stressful circumstances? We know that the delivery of fish is a behavior that strengthens the pair bond, and the lack of provisioning during that month may have damaged their bond.  I am still trying to determine if he has some parental urge to feed his young, (I have not seen him deliver a fish to the chicks, but I can't say that hasn't happened). He clearly still views this as his territory and given a chance, he wants to be there. Will they work it out? I have to say that yesterday, for the first time in recent days, all chicks had food in their crops and seemed to be doing well. The female and chicks seemed so stressed right after his return. And I have seen other single females who have been in survival mode become very stressed and very defensive towards all other males. But I have also seen a single female with chicks (whose mate had died) allow another male, unrelated genetically to the chicks, bring fish to her and remain on the nest, tho he would not directly feed those chicks. He only brought fish when the adult female was present, as part of the typical courtship behavior. He also chased away other males which offered some protection to her and the youngsters. He won himself a territory with these behaviors and was the resident male there for many years after that.  Those of you who know me, know that I relish an opportunity to learn more about their behaviors and this new situation has been a great chance to understand these birds better. But we have to refrain from making up stories about what is happening, projecting our human emotions and judgements upon them. We will continue to observe as much as possible and keep very careful notes about the behaviors we see. The good news of course is that his injuries are fully healed and he flies beautifully! Thanks to TRC for that! But we also see that just fixing up bodies is not the end of the story. The social struggles in this family of Ospreys continues.