First egg at Arb

The first egg has been laid today at the U of M Arboretum cam nest! I knew it was coming! They usually lay eggs 2-3 days apart so watch for the second egg on Tuesday or Wednesday!

Arboretum Osprey Cam

Just a quick update to let you know that the Arboretum Osprey Cam is up and running. I first saw birds on the nest in person about a week ago and read the males band then. It is the same pair of Ospreys as last year. The male is Z3, he is 8 years old this year and he hatched on a nest on private property near Carver Park. The female is unbanded, but she looks like the same female as last year. We can observe the behaviors between these two and see a sense of ease and comfort, without the tell tale defensiveness that I often see with a new pair. We are happy to answer questions here about what you see on the cam, so don’t hesitate to ask!

Now we are watching for the first egg to be laid! It should happen any day now. They have refreshed the nest with a lot of soft grasses, and we will probably see them prepare a cup for the eggs.

http://arb.umn.edu/content/live-osprey-cam

Weird spring...

It’s been a weird spring. Our first ospreys arrived in early April, right on schedule. But then the arrivals seemed to slow down and we still have some empty nests, and nests with just one Osprey, still waiting for its mate. I believe the slowness may be related to the ongoing strong north winds we have had. It seems to have really slowed down the northward movement of some of our Ospreys. We have nests that have just been occupied in the past few days! And now I am starting to see too many ospreys at many nests. Today I was watching five of them chasing and competing for a nest that has been empty throughout April. I have gotten reports of three birds on a nest from several people. I have also observed many ospreys laying down in the nest, as if they were incubating, when I knew they did not have eggs. This too may be related to the cold temps and strong winds. Sadly, I am finding many of our banded birds have not returned, yet anyway. Tho some are just showing up in the past few days, so changes may still occur on some nests. On the other hand, some of most experienced ospreys got back early and have laid their eggs. They instinctively know that the sooner they get back and the sooner they lay eggs, the greater the survival rate for their offspring.

I have been watching a nest where a long time adult male was tragically hit by a car last September. His mate had departed on her migration before he was killed, so she returned to her nest this spring not knowing that he would not be joining her. Tho I am still sad about that loss, watching a new male try to take over this territory is so fascinating... His defensiveness, his nervousness, as he brought sticks to the nest...turning away from her, hanging his head, shaking his wings. Nervously looking over his shoulder at her...and his awkward unwillingness to share his fish with this female. She even chased him around the area during my last visit. Today they seemed much more comfortable together. She is still suggesting that he should bring her a fish, as this is the true test of a good mate in the Osprey world. But they are perching near each other, seeming much more relaxed and without the defensiveness of earlier days. I am hopeful for this new pair!

Another nest fixed!

I have done a terrible job of writing posts to keep you all informed about what’s going on. As you all know, nothing is normal anymore and neither is my life. I have fewer nest monitors as people’s lives change and I am trying to watch over so many nests....and it takes a lot of time. Let me try to talk about a few things, catch up with you all in a few posts in the next few days.....first I need to send out another huge thanks to Steven Koski and Xcel energy for replacing one of the deteriorating nest poles. I was stunned to stumble across this lovely new nestpole last weekend. A before and after photo are below...not only a beautiful new nestbox, but a new pole, taller than its surroundings, which will solve lots of problems. I am so grateful for the three different crews that straightened and repaired the three different poles that were so in need of help. Wow. A million deep thanks to each and every person who played a part in helping our Ospreys avoid some potentially tragic outcomes. All of the repaired poles are now occupied! Just in the nick of time, so many wonderful people came thru for us!

2019 data update

2019 OSPREY RESEARCH AND PRODUCTION SUMMARY

                                             By Vanessa Greene

       

           The first Ospreys of the 2019 season were observed on April 6, with reports coming in from various parts of the metro at the same time. The first bands were read successfully that day. The first signs of incubation were documented on April 19. This year was a struggle for many ospreys with a higher failure rate than past years in this 36th year of monitoring the osprey population in the eight county Twin Cities Metro area.

          There were 151 nests which were occupied* by a pair of adult ospreys. (136 in 2018). There may be more nests we do not know about. There were five additional nests that were determined to be frustration nests which appeared after a nearby pair had failed to breed successfully, and therefore not counted as separate territories. Eggs were laid in 140nests (125 in 2018).There were also two additional nests that were discovered later in the breeding season and although no chicks were present, it was not known if eggs were laid or not and 93of these nests had at least one chick that was confirmed to have fledged successfully or survived to fledging age (96 in 2018). We documented 58 nests which failed (40 in 2018). We separate failed nests into two distinct subcategories; nests where a pair was present but no eggs were laid (9) and nests where eggs were laid but they failed to successfully fledge a single chick or the cause of failure was unknown (49). (Not laying eggs is considered to be a kind of nest failure by other scientists.) Out of those 49 nests where eggs were laid, there were 11nests where hatching did occur but all chicks died fairly early, before we could accurately count them. The remaining 38nests failed prior to hatching or for unknown reasons. This year’s failure rate reflects a significant increase so we looked at the statistical failure rate in recent years. In 2019the failure rate was 39%, in 2018it was 29%, in 2017it was 28%, and in 2016it was 25%. It was notable that a very large cluster of 20nest failures occurred in an approximate ten-mile square area surrounding Carver Park and the University of Minnesota Landscape Arboretum, near Victoria, Chanhassen, Chaska and Mound, MN. Most other failures occurred on scattered nests in the metro area. We do not know the reasons for these failures but in some cases, on these and other nests in other parts of the metro, we suspect that a large black fly hatch, after heavy rains, may have affected outcomes. Some adults were observed flying off the nest repeatedly during incubation. Swarms of black flies were seen on some nests with newly hatched chicks which probably succumbed to the constant biting.

There were 194 chicks that were known to have fledged successfully or survived to fledging age! (205 in 2018). Most successful nests had two chicks this year, with 41 nests with two chicks, 30nests with three chicks, and 22nests that produced a single chick. The mortality rate this year was similar to last year with 17chicks which were known to have died or disappeared before fledging, (19 last year) threechicks which died post fledge and twoadults which died; one from a vehicle collision and the other may have died from an impact injury after a territorial dispute. It was found dead near another nest on a cell tower with a severely broken wing. There were only 83adult Ospreys identified by their bands, as the number of banded birds continues to drop. Three of these were from Iowa. We located 13new nesting territories, including three nests that were newly discovered this year although reports indicated that they had been there for one or more years. Only four of these new nests successfully fledged chicks. There was one nest which was occupied by geese for the second year. It is interesting to note that of the 151occupied territories this year, 78were on osprey nesting platforms, 29were on cell or radio towers, 22were on ballfield lights, 18were on a power pole or transmission tower, twowere on other manmade structures and twonests were built in a dead tree. One of these laid eggs and produced two chicks who survived to an advanced age, but the nest blew down in a storm and both chicks died.

            The overall productivity of occupied nests which were successful this year dropped significantly to 62%,(71% in 2018, 72% in 2017, 76% in 2016, 68% in 2015, 70% in 2014, 67% in 2013, and 77% in 2012). The mean number of young fledged per successfulnest was 2.09%,(2.13 in 2018, 2.25 in 2017,2.24 in 2016, 2.43 in 2015, 1.77 in 2014). The mean number of young fledged per activenest was 1.39%, (1.64 in 2018, 1.75 in 2017,1.84 in 2016, 1.88 in 2015, 1.41 in 2014) and the mean number of young fledged per occupiednest was 1.28%,(1.51 in 2018, 1.62 in 2017, 1.70 in 2016, 1.65 in 2015, 1.25 in 2014).  These numbers reflect a notable decrease in overall productivity per nest. There were two nests which have failed for five years in a row.

           The four oldest males this year, dropped to 16years of age, with two others that were 15. Of these six older males, only two bred successfully. Our oldest female was a banded female that showed up on a nest this year for the first time and she was 13years old! This indicates that she must have been nesting previously in a territory that we don’t know about! She bred successfully.   There were four females that were 12years old, three of which bred successfully.

          It is interesting to note that we have recorded 2,467 chicks that fledged from monitored nests in the eight county metro area since the inception of this project in 1984.

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*Successful nests are those that were known to have fledged at least one chick successfully, activenests are those where eggs are laid and occupiednests are those where pairs are present at a nest site for a period of time, regardless of the time of year or whether or not they lay.

Another one of my friends is back....

I am sitting at a nest watching another one of our middle aged successful banded males, back in his territory, eating a fish. This male is very special to me. He was injured five years ago, a fractured keel, and was in rehab at The Raptor Center for a month in the middle of the breeding season, leaving his mate with three chicks to care for and feed alone. She was very stressed during that time, chasing away other males, while providing for her chicks single handedly. I discussed the issues related to releasing this male with The Raptor Center, and our fear was that his parental instincts might have turned off during that month. I released this male back at his nest with a joyful heart as he flew off with such strength....and I was stunned when his mate attacked him as if he were an intruder! She was relentless in her attempt to keep him away from the chicks and the nest. But whenever she left to get food, he would sneak in with a fish and drop it in the nest for the chicks. He never gave up trying to feed his offspring. And when the female finally departed on her migration,leaving behind three fledged chicks, he stepped in and totally provided for them until each of them became independent. The following year, when he and his mate returned to their territory, it was if nothing had happened. They have happily and successfully raised chicks every year for the last four years. This is such a wonderful story of the long term success of a rehab effort, with so many people working to get this male back where he belonged, and my observations taught me much about unusual behaviors, in unusual circumstances. Quite simply put, I adore this male and his strong parental instincts, his devotion to his offspring. It’s such a vivid memory of returning him to his territory, releasing him, and now all these years later, here he is. I just love him and am so happy that I got to play a part in his recovery, and his life. After 26 years of doing this, (2020 is my 27th season) I know so much about the histories of these banded birds, all they have been thru, and to see them return again is an experience beyond words. He has finished his fish and is working on his nest now. May 2020 be another very successful year for him!

THE 2020 OSPREY SEASON HAS BEGUN!

THEY ARE BACK! I have seen my first Osprey back on its nest and read the first band! So exciting to see a long time territorial male who has survived another migration and returned to his nest! WOO HOO! So monitors, it’s time to officially start checking nests! The 2020 Osprey season has begun!