Sunday, April 29, 2018

Still in flux.....

These early days of the Osprey breeding season are alway so interesting, and behaviors change as populations grow. When you take the time to really watch, and read bands to identify individual birds, so much is revealed. Yesterday I went to visit a nest that I discovered over the winter and I found a banded female on the nest who I had seen at another nest, with another male, last Wednesday! I have documented a lot of movement between nests and extra pair copulation over the years of studying these birds. So today I need to return to the first nest where I saw this female to see who is there now! To fully understand and document what is happening requires me to return to re read bands, reevaluate what is occurring, sometimes over and over as things are still in flux! I also visited our single Dad again to see what was happening with his potential new mate. I found her perched near the nest, eating a goldfish. She is a beautiful osprey and she is still there which is a good sign. The male arrived with a stick and worked on the nest, then he flew over to try to copulate with her, but she said, NO. She stood up very straight and did not lift her tail, flapped her wings, and off he went. It maybe that she is unsure here, or she may be too young to breed. She is unbanded so I don’t know her age. I watched this male, who I have known for so many years, thru so many different nesting sites, so many different mates. There is a kind of knowledge and understanding of the nuances, combined with knowing so much about the histories of the individual banded birds that makes each year of studying these birds more and more fascinating. We are watching the annual game of musical nests as it unfolds....when a great horned owl takes over a nest so that pair of Ospreys moves to their neighbors nest! What happens? We watch as some of our old friends do not return and a single Osprey may hedge its bets by taking up with a new potential mate, while still also waiting for its former mate to return. I hear people tell me all the time, “our Ospreys have returned” when, in fact, it may not be the same birds! To me it is often very evident by the defensive behaviors the males display. Today I recieved several different reports of nests where more than two Ospreys were peacefully hanging out together! Many ask if these are the offspring of the original pair. I doubt it. We used to band approximately 85% of all chicks and in my 25 years of watching these birds, I have documented a banded osprey returning to its natal nest only once. (And ironically, it’s our single Dad!) So what is happening? Clearly, the expansion of the population creates a great deal of competition for nest sites, but when there is no aggression shown, I suspect the birds are sending some signals that they are not a threat. Ospreys are semi colonial, so Ospreys attract other Ospreys. They seek out other birds as a way of learning if this is a good area to it free from predators? Is there a good source of food? I have seen this several times in recent years, and eventually the territorial birds usually say, OK move along now! There is still a lot to learn and I am still curious! Every year I understand a little more about them, and every year, more questions are raised that keep me captivated! 

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