Thursday, August 29, 2013

Learning to fish requires many skills...

I know I have written this all before, but it bears repeating. There are a lot of skills the fledglings need to acquire to fish successfully. They first practice diving into the water and getting lift off out of the water...tricky. Sometimes this starts with foot dragging thru the water as they fly. Then they usually try to pick up something floating in the water...a stick, or once at the hack site a young osprey brought a beer can back to us. This requires the ability to fly carrying something and land on a perch with one foot, while grasping something with the other. One of the nest monitors watched a young osprey this year fly to a cell tower with a stick, and act as if she had a fish, mantling over it. Practicing. I have seen first successful fishing attempts fall apart at this point when the young bird drops the fish when he or she lands. Eventually they will accomplish all the tasks above, and will be on their way to independence. Sigh.

How do they learn to fish?

I am reposting this post from the Dyfi osprey project, largely because of what it says about the young ospreys NOT needing to be taught to fish. This is a persistant misunderstanding around here, even being passed along to the public by people who claim to be knowledgable about ospreys. The parents do NOT teach them to fish. They innately know how and they will begin fishing when they are physiologically able. Males usually do it before females. The reintroduction here would not have worked if they needed to be taught to fish. I was one of the hack site attendants and after we translocated the chicks from northern Minnesota, I climbed up the hack tower everyday to provide food but I did NOT teach them to fish, and yet they all eventually began catching their own fish, at about the same time as the chicks in the wild with osprey parents. That doesn't mean they don't learn anything from their parents...I do believe they may follow Dad to his favorite fishing spot!
Bore da - DAY 59

Here's a short video of Cerist taken yesterday evening - eight weeks exactly after she finally broke free of her egg shell.

Her 2½ day Bank Holiday vacation seems to have done her no harm and despite only fledging just five days earlier, she is now a frequent flier.

She now has the ability to deal with her own food and even her voice has broke. She is now capable of all the vocalisations of her parents that she's heard so much of over the last two months.

Cerist, along with her sister, will stay on the Dyfi for another month or so until the free food finally comes to an end. She will almost certainly not catch her own fish however during the next month, neither will she be 'taught' how to fish by either parent. She has all the fishing skills she will ever need in her life, safely embedded in her genes. She just doesn't know it yet.

Tuesday, August 27, 2013

All fledged!

NOW I can report that all chicks in the metro area have fledged! I have visited many of the late nests in the past few days (and it has not been pleasant in this extreme heat...boy it drains  my energy). I can't necessarily say they all fledged many cases I can tho, if I have seen them all back at the nest after seeing them flying. There are some cases where I have not been able to locate all chicks at once post fledge. Since many are not banded, I am not always certain that each individual bird has made it back to the nest. I do my best tho. It does become a needle in a haystack sometimes...and chicks certainly do get into trouble far from their nests, long after fledging. That's why the mortality rate is so high the first year. I do try to be accurate with my in some cases I can only say the chicks survived to fledging age. In many cases tho, I can confidently say they all fledged successfully. A nest cannot be labeled as "successful" unless at least one chick is known to have fledged successfully. Flying away and landing on the ground and dying, is not a successful fledge.
Some of the definitions of the terms that I have used here, and are generally accepted in the scientific community are as follows: an OCCUPIED nest is one where a pair was present, whether or not they laid eggs. An ACTIVE nest is one where eggs were laid, and a SUCCESSFUL nest is one where young were known to have fledged. Many of you who know me, know how hard I work to adhere to good scientific methods, to be careful to use terms that accurately reflect documented data. I have a lot to say on this subject...but will save that for another time!

Sunday, August 25, 2013

Wow, I just went to read the Dyfi blog (from Wales) about the fledging of their chicks last week, and the disappearing act of Cerist...and much to my surprise, found that they thanked me and put a link to my blog! It's wonderful to share our experiences and learn from each other! I have learned so much from their blog and Facebook page too. I am so flattered to know they are reading my stuff and that my insights may have helped get Cerist back to the nest!

Saturday, August 24, 2013

August 24 updates...

So many funny and interesting things I could tell you all...first let me update you about the situation where one male has two nests and six chicks. He has been very scarce...understandably. I never see him at one nest...but yesterday I found two of his three chicks at the other nest whining desperately for food. The female arrived with a big fish and one chick began devouring it. Then an unbanded male arrived and perched for a while...Hmmmm....but was followed shortly by the banded resident male carrying a large, half eaten fish. He chased the visitor away and disappeared. He finally returned and ate the fish without sharing it with his family. Good to know he is alive!
Today I visited the nest where the young female moved herself and was adopted. She was on the nest, and another juvenile was on one end of the nest perch. A third youngster arrived and tried to land on the nest but the adopted sister chest butted the other chick off the nest. He returned and perched on the other end of the perch. He slowly moved closer and closer to the nest, but when he moved onto the nest, the adopted female rose up and so did he, pushed her off the nest and a chase ensued. She is being quite the bully. He perched nearby and they all food begged and whined. I was there for over 90 adults arrived. Just the eruption of these little skirmishes. I believe she was positioning herself for a fish delivery, so she would have the advantage at getting it. She has won the battle for food in the past. Funny part was when I left and drove down another road on the other side of the hill from the nest, I found Mom and Dad, sitting side by side, male eating a big fish!!!! Avoiding the kids.
I can also say that while visiting many nests in the past few days, I have only seen a few females. Many males remain perched high in their territories, watching over their offspring and their kingdom. I also can confirm that only one chick remains unfledged, as of today. I will keep watching her. It's going to be a tough week with record high temps expected with very high humidity. It's a good time to learn to fish!

Fledging is so hard to do...

I am sitting here watching a young osprey who has not fledged yet. Her sibling is zooming around, landing on other perches and I believe I heard him saying "weeeeeeeeeeeeeeeee" as he flew. She hopped up onto one of the ceramic insulators on the power pole which holds the nest. Her foot was slipping and I thought she was going to slide down and catch her foot or leg. I was mentally planning a rescue, but she hopped back into the nest. Whew. The adult male has been coming and going with sticks. No sign of the female. It's been interesting to observe the effects of the late spring, with the delay in egg laying and hatching. Some females appear to have taken off on their southerly journey at the normal time, even if they still had young, unfledged offspring...or fledglings that are still returning to the nest frequently for food. Other adult females are still near their nests, watching over their youngsters. I am still checking on a handful of unfledged chicks. I fear that their chances for a successful migration are slim, given their lack of fishing skills and their dependence upon their parents. Can't believe I am still watching for fledging in late August!

August 20...

It's been a while since I posted...busy checking on all those chicks! Some have ended up on the ground, some figured out how to get going on their own, some did not. One had to be placed in a neighbor nest since its home was on a cell tower...but it was cared for there until it was able to get back to its nest on its own. In another interesting twist, a chick moved herself to another nest where she was adopted by that family! She was not just visiting...she moved in! Interesting! And there are still a few chicks that have not fledged! I am trying to account for all chicks, but sometimes it's not possible. But we do try! Many chicks disperse this time of year, especially the males, tho we may see them again before they begin their migration. Some adult females are not being seen on the nests anymore and I am sure they have begun to head south. It's interesting how different the adult males behaviors are...some are so attentive, watching over their offspring, providing food whenever a food begging voice is heard. Others seem oblivious, ignoring the chorus of hungry voices. There are a variety of situations that have us concerned, so we watch over those birds carefully. I am so thankful for all of the people who have checked on the ospreys, alerted me to potential problems, and who take time out of their busy days to help assure the welfare of our winged friends.

Wednesday, August 14, 2013

Polygyny update

Update on the polygyny case...the last chick has fledged! So the male that produced six chicks at two nests was successful! It's amazing. I am watching the littlest chick flying loops, sticking his landings and food begging. There he goes on another loop around his home territory. He flies low and barely misses things...makes me nervous, but he made it back to the nest with one of his siblings. What I am not seeing, is the male or the third chick. The chicks are food begging, so the female just took off. Did she go to get a fish or to get the male????


Very interesting day in the field. I believe that some females are getting ready to leave already. I have been struggling to read a federal band with eight digits on a female all season, and I have all but that last digit! In recent visits she is feeding herself rather than her chicks, who have fledged. She has been gone for long periods of time, flying off as far as you can see. I suspect those females lose some muscle mass after all the incubating and then all the brooding, standing guard, shading. She seems to be needing to do some serious flying to get ready for migration. Alas, she has been hard to find as I try to get that last digit. I have seen other females perched alone, chicks off with Dad. We still have chicks that haven't fledged at this late date too. What a weird year. I also observed some very interesting and different behaviors today...some things I need to follow up on and revisit before I make sense of it all and post. I still am learning new things, seeing new things and scratching my head a bit. Love it. I get so excited sometimes by what these birds do. 

2012 data analysis...

I have gotten way behind on this is the synopsis of the 2012 results:
The year 2012 began as a warm and early spring for the Ospreys in the 8 county metro area surrounding Minneapolis and St. Paul, Minnesota. There were no major storms that caused mortalities in the population. Once again there was a significant increase in overall number of occupied nests. There were 90 nests which were occupied* by a pair of adult ospreys, although two of these were determined to be alternate / frustration nests which were occupied by a pair counted at another nest site nearby. As a result, there were 88 nests that were counted as being occupied territories. Eggs were laid in 83 nests (73 in 2011) and 68 of these nests had at least one chick fledge successfully or survive to fledging age (56 in 2011). There were 20 nests which failed (24 in 2011). There are two distinct subcategories under failures; nests where a pair was present but no eggs were laid (five) and nests where eggs were laid but they failed to successfully fledge a single chick (15). Not laying eggs is considered to be a kind of nest failure by other scientists. There were 140 chicks that were known to have fledged successfully or survived to fledging age. There were three chicks which died / disappeared before banding time, and six additional chicks which were known to have died between banding time and fledging, or around fledging time. There were only 57 chicks banded, (using the green / black color band and a silver USFWS band) and 83 remained unbanded (only 41% banded compared to 71% in 2011, and 80% in 2010). This is a significant drop in the number of chicks banded which will affect future research. There were 88 adult Ospreys identified by their bands. Two of these were purple/ lavender bands from Iowa. There were 10 new nests; nine with eggs laid and and one with a pair present but no eggs laid. In addition, there was one nest which was reported for the first time, although it had been active for several years. Nine of those new nests successfully fledged chicks. There were 12 banded Ospreys which were believed to have bred successfully for the first time and their average age was 4.5. (Average age of first successful breeding for males this year was 5.0 years and for females it was 3.0 years).
The overall productivity of occupied nests which were successful rose this year to 77% (70% in 2011, 73% in 2010, 67% in 2009, 65% in 2008). The mean number of young fledged per successful nest was 2.05 (1.94 in 2011). The mean number of young fledged per active nest was 1.68 (1.49 in 2011) and the mean number of young fledged per occupied nest was 1.59 (1.36 in 2011). These numbers reflect a rise in productivity after dropping last year.

Wednesday, August 7, 2013

After the storm...

I checked nests after the storm last night and the nests I visited on the western and northern side all seemed fine. I found more chicks fledged and I noticed that the leaves are already starting to change. Seems early. I had an interesting few hours at one of the nests whose original male was tending to two nests. There was an over abundance of ospreys flying around near the nest...five at one time. They returned several times, chirping, circling, socializing, with no apparent aggression. The most interesting part was that one of these visiting males was doing a sky dance, a part of courtship behavior, high in the sky above the nest with a fish in his talons. The chicks were food begging much of the time I was there. It seemed as if the female was hesitant to leave her chicks to get some food with all the extra ospreys in the vicinity. When things quieted down at one point, she left. It was during her absence that the sky dancing male with the fish landed on the nest. It was NOT her former mate. Tho the chicks were hungry, one of them lunged at the male...I wonder if it was to grab the fish or to suggest that he leave. Leave was what he did. The female returned with a fish 23 minutes after she left and she was followed by an unidentified male. He did not land. The sky dance started up again above the nest, and that male came back and landed on the nest while the female was there. She did not attack...there was a raucous arising of food begging by all, which seemed to scare him off again. So it seems she is attracting some new, potential mates. I did not identify her former mate during all this commotion. This all must be stressful for her. The chicks are doing allright, tho hungry.

Friday, August 2, 2013


I would like to elaborate on something mentioned earlier which seems to have raised questions. It relates to behaviors during the early post fledging time. When an osprey chick flies for the first time, they do not have the skill level that an adult has. I mentioned that if they land on the ground, they usually can't get going again from that position until they are stronger and have developed more skill. Adult ospreys do not usually feed a chick that ends up on the ground. Feeding at that stage of development occurs on the nest. If a rescuer finds a chick on the ground, they may try to place a chick on a fence or in a tree. This is done to facilitate the young birds take off, to return to the nest.(and to prevent predation by ground predators). This does not mean the chick will get fed there. In my 20 years of watching young ospreys fly for the first time, I have seen them land somewhere, like on the ground, in a tree or telephone pole and sit there food begging for many hours, perhaps even a day or more. I have NOT seen the adults feed them there. I have frequently observed the adults flying around the stuck chick with a fish, and then flying to the nest, as if to lure them back there to eat. Feeding occurs at the nest for 10- 20 days after fledge. Young ospreys do not seem to have the dexterity to perch and hold a fish to eat at first. It won't take them too long to develop those skills, but at the time of the first few flights they usually need to return to the nest to get fed. It can seem cold to see adults ignoring a young osprey desperately food begging, but perhaps they instinctively know that if the youngster can't fly well enough to get back to the nest, it is not a wise investment of their energy to feed it. Sometimes human intervention can change the outcome, but sometimes not. I have seen chicks repeatedly jump or fall out of a nest, and putting it back in the nest several times did not help. Some chicks just don't develop properly and do not survive. I always think its worth a try. This is contrary to the behaviors of some other birds. I have rescued songbirds who fledged too soon many times, placing them in a high perch and the adults will feed them there. I can't explain why ospreys behave differently, I can only report what my observations have been over 20 years.