Saturday, April 19, 2014

Friday, April 18...

I will have more to post later but I am at the Arboretum watching the nest that is on the cam. The cam is on...http://www.arboretum.umn.edu/ospreycam.aspx
And I have identified both birds on the nest as the same ones as last year, including our elder statesman, 79, who is 22 yrs old this year! His mate is 3S, a four year old. There is currently a big brou haha here with five ospreys flying around, chasing. One of them hit the other so hard I heard a loud thud and the bird ended up on the ground. I was preparing to rescue when it finally got up and rejoined the chase. So far the old guy is defending his territory! Welcome back old friend! Several different males have been sky dancing at the same time, to win this females heart! Love that old guy...hope they are successful this year. Stay tuned...

Wednesday, April 16, 2014

Monday morning, April 14...

Good morning ...after checking nests all day yesterday I was too tired to post last night. I visited 24 nests, read twelve bands and have driven over 400 miles this past week. We do have a serious game of musical nests going on...ospreys identified on different nests than where they have been in the past. Doesn't mean they will stay there! I have been dismayed to see at least three nests removed from cell towers over the winter. The Ospreys can rebuild them in a heartbeat tho and they are determined! I am also seeing a number of new, young birds who are nesting for the first time.
This is also a plea for help...several of my volunteers are unable to check nests due to health issues so I do need help watching over all these nests. If you would like to get involved, watch a nest or two or three, learn about osprey behavior, spend time in the field with me, please send me a message. It takes a village!

Saturday, April 12, 2014

Friday in the field...

What an interesting day in the field! Seeing old friends,(people and birds), observing behaviors and documenting the big game of musical nests! I visited ten nests, but had to go back and forth between them to figure things out, and it took me some time to read five bands. Three of those nests were still empty. Three of them had only one bird, and four of them had pairs present. Funniest part was seeing a male who I have not seen in about 7 years or so! He is 12 years old and showed up at a nest where the male disappeared last year and is presumed dead. Where has he been all this time??? AND he was with a female from another nest that failed last year...while her old mate is waiting alone for her. They seem to be taking over a nest...I wonder how this one will end. Jeeezzzz, it's so interesting. I also received several more emails with excited reports of birds back on their nests. So many nests to visit, and so many bands to read. Time is an issue...never enough.

Wednesday, April 9, 2014

First full day in the field...

My first full day in the field checking nests...some interesting observations. Overall, I visited 22 nests and found five nests with ospreys. There were a pair of birds on three nests and one bird on two nests. I saw extra ospreys flying around at two of those sites. I read three bands. Most lakes near the nests were still frozen. Many of you remember the saga last year of one male who was attending two nests, with three chicks in each. Today one of those nests had a new male. He was copulating with the female there tho I was unable to determine conclusively if she was the same female as last year. It remains to be seen what happens if the territorial male returns.  He may chase off this new male. I believe they sort of instinctively defend territories where they successfully reproduced. The female may have a say in the matter also as she might jump into the fray and help chase off the very male she has been copulating with, or she may stay out of it and let the males duke it out. Usually a territorial male can easily displace any other males who might try to take over. His  other nest was empty. Perhaps one of the females won't return. Perhaps that will solve the dilemma. Perhaps he won't return! There are many scenarios possible. I have seen males defend two nest sites even if they were only breeding at one...defending the other one against any other ospreys, only to use it as a perch. Ah the drama goes on. Still so much to learn!

Sunday, April 6, 2014

They're back!

I received several reports of Ospreys back on their nests today! The warm front has carried some of our winged friends back home at last! I spent some time watching one of my old friends working on his nest this afternoon. So osprey season has officially begun!  We're off and flying...

Sunday, March 30, 2014

2013 OSPREY PRODUCTION SUMMARY...


The year 2013 began as a very late and snowy spring for the Ospreys in
the 8 county metro area surrounding Minneapolis and St. Paul,
Minnesota. With so many lakes still frozen, many Ospreys did not
return to their nests as early as they did in 2012. We did receive
reports of Ospreys as early as March 20, but many did not arrive at
their nest sites until mid to late April. Once again there was a
significant increase in overall number of occupied nests. There were
105 nests which were occupied by a pair of adult ospreys. In
addition, there were three nests where ospreys were only seen briefly,
and two nests where only a single osprey was observed. Eggs were laid
in 94 nests (83 in 2012) and 70 of these nests had at least one chick
that was confirmed to have fledged successfully or survived to
fledging age (68 in 2012). There were two additional nests reported
that were not confirmed as successful. The mortality rate was high, 
with 33 nests that failed (20 in 2012). There are two distinct subcategories 
under failures; 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 (22). There were two additional  nests, discovered late
in the season, where it was not known if eggs were laid or not, but
no chicks were observed.  Not laying eggs is considered to be a kind
of nest failure by other scientists. There were 146 chicks that were
known to have fledged successfully or survived to fledging age. (there
were two additional chicks reported that could not be confirmed).
There were two chicks which died / disappeared before banding time,
and 15 additional chicks which were known to have died between banding
time and fledging, or around fledging time.  Two additional adults
died or disappeared midseason.  There were 98 adult Ospreys identified by 
their bands. Three of these were from Iowa, one was from southern Ontario 
and one was from Wisconsin.
There were 22 new nesting territories (this does NOT count nesting
territories that have been active in the past, were unoccupied for one or
more years and then reoccupied) ; 15 where eggs were laid. One of
these nests was reported for the first time, although it had been
active for several years. Twelve of these new nests successfully
fledged chicks.  There were 15 banded Ospreys which were believed to
have bred successfully for the first time and their average age was 4
years old. (Average age of first successful breeding for males this
year was 4.1 years and for females it was 3.8 years).
The overall productivity of occupied nests which were successful
dropped this year to 67%  (77% in 2012, 70% in 2011, 73% in 2010, 67%
in 2009). The mean number of young fledged per successful nest was
2.08 (2.05 in 2012). The mean number of young fledged per active nest
was 1.55 (1.68 in 2012) and the mean number of young fledged per
occupied nest was 1.39 (1.59 in 2012).  These numbers reflect a drop
in overall productivity, with a slight rise in the number of chicks
per successful nest. 

I will post a new entry soon with an explanation of terms, and thoughts on research 
methods.

Friday, March 21, 2014

March 21, 2014

I am still doing final counts on my tabulations from 2013 to be SURE the numbers are accurate...meanwhile, as we wait for the birds, I know many of you are interested in the stories of specific ospreys. I find myself thinking of four ospreys in particular. One is the male who will be the oldest this year. Mr 79 who has nested for many years at the Arboretum (which now has a cam on it) will be 22 years old if he survived another migration. He has a history of being a late return to his territory. His mates have often beat him back and engaged in some extra pair copulation and he has had to chase off some other males. Last year he got a new, young female, but their nest failed. I am anxious to see if he makes it back. The second oldest male would be Mr B4. He would be 21 this year. He has been a reliable male, with several mates but this would be his 13th season with his mate, if they both survived. He is the last of the hacked birds from the reintroduction. He was translocated from northern MN and released at the Cedar lake hack site. He returned to MN when he was two years old and spent that summer hanging around the Medicine Lake hack site, where I was the hack site attendant. He then nested on Mooney lake in Wayzata in 1996, moved to a nest on the lights at Wayzata West Middle School in 2001, and then moved to a nest on private property on Robinsons Bay and has been there since 2004. The oldest female will be 20 this year and is nesting on the Lake Minnetonka Regional Park Cell tower where she has been since 2000. The other female that I am anxious to see is the female on the Edina nest who had some eye issues last year. I hope she could see well enough to care for herself and to survive another migration. She was hacked out in Iowa and will be 12 years old this year. Those of us who have been watching these birds for years grow very fond of our winged friends!

PS Hacking is a falconers term...it is a technique for slow release of non flighted birds. This population of ospreys is the result of reintroduction efforts. Nestling ospreys were collected in northern MN and translocated to several hack sites in the metro area. A hack box is a large box(6ft x 6ft) on scaffolding with hardware cloth on the outside to protect these non flighted chicks from predation and yet to allow them to see their new home territory. I was one of the hack site attendants who fed the chicks small pieces of fish twice a day until they developed enough to be ready for flight. We had several different methods for releasing them when they were ready. They flew and learned to fish while we continued to provide food for them until they naturally dispersed. They imprint on the area where they learned to fly and return when they are old enough to breed. So B4 is a bird who went thru that process and returned to nest and has produced 38 chicks.