Monday, May 21, 2018

Arboretum cam nest....

For those not reading the Facebook page, the Arboretum cam nest laid it’s first egg on May 3-4, the second egg on May 7 and the third egg on May 10. Like clockwork, every third day! They gave us a scare when the male brought a large sheet of plastic to the nest and the female struggled with it....at one point it was completely covering her. Viewers were concerned that the adults would die, but they are always free to fly away and were in no danger. The concern was for the eggs. I watched another nest many years ago where the male brought some landscape fabric to the nest and when it covered the eggs, and they could no longer see them, they quit incubating and the eggs died, the nest failed. But in this case, although it was very frustrating to observe, the plastic got moved to the nest edge and finally blew away. Whew!
Ospreys are known for bringing interesting things to their nests. Over the years we found many funny things in the nests during banding, a lanyard with keys attached, hats, gloves, an arrow, etc. They  are also known for bringing dangerous things to the nest, like baling twine. We have rescued too many chicks that became tangled up in it. Last year I found a chick hanging dead from the nest edge tangled in orange baling twine. It wasnt the first time either.
Here is the link to the cam... http://www.arboretum.umn.edu/ospreycam.aspx

May 20.....

It’s been a crazy few weeks but I will try to share some interesting stories with you about our Ospreys. First of all, I know that many of you are curious about our single dad from last year. He did find a  beautiful mate. I visited the nest many times and without exception, every time he tried to copulate with her, she was unreceptive (would not lift her tail) and the attempt was unsuccessful. I was beginning to think that perhaps she was too young to breed. It was discouraging to think that a whole breeding season might be wasted for him. But he and his new mate are now incubating eggs! Of course the amount of time I was at the nest may have only been several hours in a week, so there surely were many copulation attempts when I was not there. I do wonder if the eggs will be fertile, but once again I am keeping my fingers crossed for this fellow. 
 Me and my team are still working hard on getting the bands read, tho every year there are fewer banded birds, which is rapidly destroying the behavioral research. We still are hoping to find a master bander who wants to get involved and help us remedy this situation. We have documented a lot of movements between nests among the banded birds and I am still sorting out final territories! Most Ospreys have laid eggs now, which makes the band reading more difficult and can take many  hours as we wait for the birds to switch places. And often when they do take their shift on the eggs, the exchange can happen so quickly that all we can determine is IF a bird is banded or not. Females tend to stay closer to the nest during their break time, but the males often disappear. We are learning patience and perseverance! Because the birds do move around a lot in the early part of the breeding season we have to read and re read bands. Usually by the time eggs are laid, the game of musical nests has settled down. Most incubation dates are several weeks later than in past years so it will be interesting to see how this impacts overall productivity. Will we see more Ospreys remaining here until late September or October this year? Will we see fewer chicks on productive nests or more failed nests? We are finding new nests, and have at least six  so far that were not included in last years count. I am very sad to report that two of our oldest males did not return this year. They were 23 and 18 last year. They have been replaced by unbanded birds. I have known both of those birds for so long.....there have been a lot of goodbyes in recent years, the result of doing this research for 25 years. 

Wednesday, May 2, 2018

A threesome?

Life remains pretty darn interesting in the Osprey world! I am still documenting a lot of musical nests....birds moving around, some still waiting for a mate, or looking for a mate. I am finding nests that have been unused for several years are suddenly reoccupied, have found several new nests already this year as well. Today I found a nest with two females and a male on it! The females were coexisting peacefully, one had a fish, the other was just waiting calmly as the male ate a fish nearby. I did not see any copulation, which might have given me some clues about what is actually occurring. Is there just an extra female being tolerated temporarily by a bonded pair....or is it really a threesome, with both females getting food and copulating with the male? Hmmmmm. I visited a lot of nests and covered 120+ miles, read some bands and found a lot of unbanded birds. Yesterday I revisited the single dad and found him still hanging around with the new female. I have not seen them copulate successfully yet but I am hopeful tho!
There are still so many bands to read and the light is just not cooperating. I really need some cool cloudy days to help me get the bands documented. I am finding more and more nests that have laid eggs. There are so many nests that I have not even gotten to once this year....my time has been so limited lately. I know we have a lot of new readers who may be looking for basic information so do feel free to ask questions! The books say that Ospreys incubate between 35-43 days and many years ago, when I had only a few nests to watch, I determined that they most often hatch on day 39. Researchers in Pennsylvania also arrived at the same number. Of course there can be some variation, especially if the first egg does not hatch. I see that osprey researchers in other places have come up with a slightly different number. During this phase, both male and female will incubate so we watch for the changing of the guard. Usually when the male brings a fish, the female will take it and leave to eat her fish nearby. The male will then take over the incubation duties. In fact one of the tell tale signs that hatching has begun is that the female will NOT leave with the fish, but will begin taking small bites and leaning into the nest cup to feed the wee ones that can’t be seen at first. So this is a behavior to pay attention to....the alternating of incubators, so that when this behaviors changes, we can recognize the early signs of hatching.

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 live....is 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! 

Friday, April 27, 2018

Update on Mr Mom....

As I was out and about today, I visited the nest of our single Dad. Yesterday I found no one there. Today, at first, the nest was empty but then I saw an Osprey gliding towards the nest, but he kept going, circled around, went up high and started a sky dance! Then I saw her, the other osprey, for whom he was dancing....she landed on a favorite perch of his former mate. He danced for her for quite a while, they flew around together....but it doesn’t appear as if it is a done deal. I told her that he is a great mate, and she would be hard pressed to do any better. I had to leave for an appointment, but am hopeful. He is trying to get a girl! I also found several more Ospreys incubating. Have gotten a lot of lovely bits of info from the public.....people I don’t know, just sharing photos, observations, return dates of their favorite Ospreys, etc....it’s heart warming to know the public is watching, and is aware of my efforts, a lovely network is being created!

Wednesday, April 25, 2018

April 25...

What a lovely day.....I visited 15 nests and still had many more I had hoped to get to, but didn’t. Sigh. Sometimes bands can take a long time to read, especially on such a bright sunny day. I did visit the arboretum cam nest and both Ospreys are back on the nest.....Z3 was there with an unbanded female, just loafing. It was interesting how many nests had a lone female, waiting.... presumably because the males are having to travel further to get fish with so many lakes still frozen. But some birds were eating so they are finding food! I saw one male struggling with an enormous fish, looked like a pike! Lots of copulating, sky dancing, extra birds chasing.....clearly there is a great deal of competition for nest sites. Some new birds have shown up on nests, which may mean we have lost some of our old friends. But some nests are still empty so we still have Ospreys that have not made their way back to Minnesota. Things are still in flux! Thanks for all the reports, emails from the nest monitors as well as the general public! I appreciate each tidbit of info that is shared! I always enjoy the conversations about behaviors, bird histories, research goals and each chance to share my passion for these birds.

Sunday, April 22, 2018

Fun in the field!

Finally a warm day and some free time to check nests. I visited 13 nests and 7 of them had at least one bird, 6 nests were still empty. I saw 12 Ospreys and read two bands. At two different nests I observed three Ospreys flying, and interacting. None were aggressive. At one nest I watched TWO males sky dancing at the same time for a female that was standing on the nest, seemingly unimpressed. One male landed without a fish and he turned his back, hung his head, and shook his wings. This is a defensive behavior. I often see it with a new pair of Ospreys, but I suspected this was her long time mate as he had a band, tho I was not able to read it in the short time he was on the nest. The female eventually lunged at him, and he flew off. The other male was sky dancing with a fish and he finally delivered it to her. He was unbanded. She took the fish to a nearby perch to eat as the male moved sticks on the nest. He tried to copulate with the fema,e but she said, NO! Then the banded male returned, without a fish. I watched for nearly two hours as the behaviors were interesting, unsettled, and I am always captivated by the way these birds interact, they way they renew old bonds, the way new birds try to find a way to win a territory and a female.
So our Osprey season is picking up the pace, new birds finally arriving on these warm southerly winds. I wish I had more time to spend in the field...there are so many nests to check, new volunteers to meet, and bands to read. Thanks to the monitors who are visiting so many nests and band reading as possible. We have our work cut out for us! It was nice to be out there, listening to the courtship songs, watching these beautiful birds and remembering why we love them so much!