Thursday, January 28, 2021

2020 results!

 Here are the data results for 2020, for those who are interested in the numbers! 

                 2020 OSPREY RESEARCH AND PRODUCTION SUMMARY


                                              By Vanessa Greene


          The first Ospreys of the 2020 season were several territorial males that returned to their nests on April 1-2, with their mates returning the following week. The first birds to return were also the first to lay eggs on April 15. It was a good year for the Ospreys in the metro area in this 37th year of monitoring the osprey population in the eight county Twin Cities metro area, with increased numbers and a higher success rate than last year.

           There were 159 nests which were occupied* by a pair of adult ospreys. (151 in 2019). There may be more nests we do not know about and we hope the public will continue to report new nests to us. Eggs were laid in 144nests (140 in 2019). There were four additional nests that were discovered late in the season with either no birds present (2), one bird present (1) or in one case, a dead adult osprey hanging on the side of the nest, which could not be included in the above counts without more information. Some of these nests may have been frustration nests. There were 116 nests had at least one chick that was confirmed to have fledged successfully or survived to fledging age (93 in 2019). We documented 43 nests which failed (58 in 2019). We separate failed nests into two distinct subcategories; there were 15nests where a pair was present but no eggs were laid (9 last year) and 28nests where eggs were laid but they failed to successfully fledge a single chick or the cause of failure was unknown (49 last year). (Not laying eggs is considered to be a kind of nest failure by other scientists.) Out of those 28nests where eggs were laid, there were 8nests where hatching did occur but all chicks died fairly early, before we could accurately count them. The remaining 20nests failed prior to hatching or for unknown reasons. This year’s failure rate reflects a significant decrease!  The 2020 failure rate dropped to 27%. (In 2019the failure rate was 39%, in 2018it was 29%, in 2017it was 28%, and in 2016it was 25%.) We were encouraged to experience no repeat of the devastating black fly problems that occurred last year.

          There were 237 chicks that were known to have fledged successfully or survived to fledging age! (194 in 2019). Most successful nests had two chicks this year, with 47 nests with two chicks, 37nests with three chicks, and 32nests that produced a single chick. The mortality rate this year was lower than last year with 8chicks which were known to have died or disappeared before fledging, (17 last year). There were two known adult mortalities. One was a female that was found injured below a nest in early April, was taken to The Raptor Center where she had to be euthanized. The other was the adult osprey found hanging dead from the side of a nest that was discovered in early September.

          There were only 74adult Ospreys identified by their bands, as the number of banded birds continues to drop. We were sad to document that there were 18banded birds that did not return this year. Three of the returning banded ospreys were from Iowa.

          We located 20new nesting territories with a pair present, including at least one nest that was newly discovered this year although reports indicated that they had been there for more than one year, and 11of these new nests successfully fledged chicks. There was one nest which was occupied by geese and one that was occupied by Great Horned Owls. It is interesting to note that of the 159 occupied territories this year, 75were on osprey nesting platforms, 30were on cell or radio towers, 26were on ballfield lights, 24were on a power pole or transmission tower, twowere on other manmade structures and twonests were built in a tree.

          The three oldest males this year, were 17years of age, with two others that were 16 and 15. Of these five older males, two bred successfully, two others produced chicks that survived to an advanced age but did not fledge successfully, and one male failed to breed. Our oldest female was 14years old and she bred successfully.   There were four females that were 13years old, which all bred successfully.

          The overall productivity of occupied nests which were successful this year increased to 73!  (62% in 201971% 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 2.04%(2.09% in 2019, 2.13 in 2018, 2.25 in 2017,2.24 in 2016, 2.43 in 2015,). The mean number of young fledged per activenest was 1.65%(1.39% in 2019,1.64 in 2018, 1.75 in 2017,1.84 in 2016, 1.88 in 2015) and the mean number of young fledged per occupiednest was 1.49%(1.28% in 2019,1.51 in 2018, 1.62 in 2017, 1.70 in 2016, 1.65 in 2015).  These numbers reflect a notable

increase in overall productivity per nest. There was one nest which has failed for six years in a row, but one nest that had failed for five years was successful this year!

          It is interesting to note that we have recorded 2,704chicks that fledged from monitored nests since the inception of this project.

           

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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.

 

Monday, January 25, 2021

2020 ACKNOWLEDGEMENTS

 2020 Acknowledgements

 

 

 

There are so many people who have been instrumental in helping Twin Cities Metro Osprey Watch continue this Osprey research. This year, 2020, marked my 27th year of monitoring all known nests in the eight-county metro area surrounding the Twin Cities of Minneapolis and St Paul, and I could not do this without a great deal of help. The careful, monitoring of these nests and the consistent collection and analysis of data over so many years may prove to be a significant contribution to understanding the world we live in, the health of our environment as well as overall productivity and behavior of this population of Ospreys.

Special thanks to Barb Ankrum,  Carol Christians, Perry Westphal, Dani Porter Born, Meg Smith, Ellie Crosby, Debbie Jordan, Ann Merritt, Larry Luebben, Jack Kimmerle, Pat Norton, Laurie Gillis, James Misuraca, Jerry Hendrickson, Ken Fischer, Holden, and  Larry Waldhauser, for sharing their observations, their commitment to this effort, their photos, and their love for these birds. We had fewer nest monitors this year, partially due to the pandemic that kept so many people at home, and I am deeply, profoundly grateful to those who kept their commitments and kept an eye on their nests throughout the season. I cant do it all alone.

Thanks to all the private property owners who are such important and wonderful hosts to our Ospreys, and who have provided me access to these nests for monitoring.

A very deep, heartfelt thanks to all who contributed financially to this project in 2020: Barbara Pierson and Paul Patton, Ruth Rechtzigel, Debbie Jordan, Robert Van De Loo, Catherine Cohen, Michael Academia, Judith Notari, Tamalyn Page, Alisha Medellin, Gail, Barbara Ankrum, Susan Light, Pat Norton, Bernice Caruth, and Phyllis Bofferding! 


I am deeply grateful for all the help I have received in so many different forms, and for showing your faith in my ongoing efforts to continue this research study.

 

 

Vanessa Greene     

February 2021

Osprey.mn@att.net

Osprey.mn@gmail.com

“Twin Cities Metro Osprey Watch” on Facebook

Ospreywatch.blogspot.com

952-935-1883

Friday, January 15, 2021

 Is it too late to wish you all a happy New Year?

I am working on the annual report.....this is day six of gathering data, making charts, adding up numbers, searching the 200 pages of field notes, checking with some volunteer monitors to clarify some details, and finally today I am actually writing up the results of the analysis. I think I have the first paragraph completed. The numbers look better than last year....much better year for our Ospreys here in the eight county metro area!