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Thread subject: Some Osprey Mating Info
Name Date Message
Celeste 04/01/05 07:31 pm In searching for an answer to Melanie's questions I came across the following....."An Osprey's mating call consists of a brief "hew" and is repeated many times. To mate, the male has to get on top of the female's back. The female has to bring her tail up while the male brings his down. When mating, Osprey have to be careful about hurting each other. For example, a male will ball up his feet to avoid hurting the female with his talons during mating".

I was not successful in learning when ospreys stop mating and wait for the eggs....I am inclined to think however, after reading several sites regarding mating and osprey, that they may continue mating until the hen lays the eggs. Osprey will lay 3-4 eggs and must maintain a temperature of 100 degrees F.
The eggs hatch from 32-45 days and the nesting period is 44-59 days.
Cecilia 04/02/05 01:14 pm Poole doesn't address the subject of age in relation to copulation frequency in the book I have, "Ospreys - A Natural And Unnatural History" but he does have some interesting things to say on the subject of copulation position, behavior and successful nests:

" Once Ospreys settle at a site and start courtship feeding, mating can occur at almost any time or place. Males mount females gently, talons closed and tarsi resting somewhat precariously along the female's back; vigorous flapping helps the male maintain balance. If the female is receptive, she tips forward to allow the male's tail to scissor under hers. She usually maintains this position briefly after the male dismounts. Successful copulations, those in which the cloacae touch, apparently depend on this forward tilt. Unreceptive females refuse copulations by keeping a horizontal posture or by tipping back on their tails, so males just stand there flapping or slide off. Failed copulations are common. Young pairs are less likely to copulate successfully than old pairs (37% vs 72% : Poole 1985), largely because young males are reluctant to transfer food, leaving their mates unreceptive to breeding.

Most copulations take place at the nest because females spend most of their time there, but they can occur anywhere. No elaborate ritual or display precedes mating. Females sometimes appear to solicit copulations by tipping forward with raised tail and dropped wings (Sailler, 1977), but this is subtle behavior and hard to decipher. At other times, it seems that the males mount with no signal from from their mates, flying in from behind (like Yeat's Zeus landing on Leda) or fluttering up onto the female from the nest edge. Only 24 of 93 attempts at copulation by male Ospreys occurred during feedings (Poole, 1985), so apparently food is not the immediate stimulus for mating. Pairs mate most frequently just prior to egg laying. Earlier copulations may have little to do with fertilization, serving instead to test a mate's receptiveness (strengthen the pair bond) and to synchronize the development of the gonads. This latter aspect is especially important because females probably arrive back at nests each year with ovaries only partially developed, then going through a period of rapid ovarian development. In this phase, ovaries gain 5 to 15 times their initial weight before descending the oviduct (Lofts & Murton, 1973)."

I'm wondering if we have seen Betty tip forward during the various attempts we have seen Dennis make. There are photos in the book, that I wish I could show you, in which the female is tipped up at a 45% angle with tail almost vertical and her beak touching the nest as the male stands on top. I don't think I have witnessed a copulation yet that looked like these pictures...which makes me wonder if we will see eggs this year.

Poole also mentions that females in older pairs are fed more than females in younger pairs. It seems like that is just what we've seen. And it also points to an inexperienced male. We've all felt that he looks young, for a variety of reasons, and she sounds young...and Poole says that Ospreys tend to pair up with Ospreys their own age, except in some areas where nest sites are limited or older Ospreys have lost a mate...then they tend to take a much younger mate because most of the avilable birds are younger. So all of this seems to verify that we're watching a young couple (3 yrs. maybe) and it's no wonder that they are so active sexually!
Celeste 04/02/05 03:14 pm I was wondering the same thing as I read your report from Poole....don't remember ever witnessing the female tipped either....for that matter I wasn't conscious of it last year. I think we all agree that this is an inexperienced couple especially compared to the last two will be several days more before we know for sure whether or not we will have be continued......
Tim P 04/02/05 04:59 pm First, thank you Cecilia for the information.
I honestly hadn't known about the 45 degree position. A few days ago I referred to the female as being receptive during copulation. At that time she just appeared more cooperative to the act, in hindsight I do believe she was at the 45% angle and also earlier today she seemed to cooperate with tail in the air. According to the information you provided here the earlier attempts strengthen the pair bond & help development of the gonads. They may not have been successful at fertilization but I do see the bonding of the pair taking place. Most attempts I̢۪ve seen have occurred as the male is flying in from behind which was followed up by the fluttering up onto the female from the nest edge or following her to the cam perch. It̢۪s been very interesting watching two new youngsters develop into a pair. While observing the older more experienced pairs on this camera some of the dynamics we see now weren̢۪t displayed as a result of them being experienced. Thanx for sharing the book.
Cecilia 04/02/05 05:42 pm At 5:19 I was sitting here doing some backing up when I noticed that Dennis was on top of Betty and yes! she definately was tipped forward, he eventually got down into a more crouched position and after a few seconds of staying that way he moved off. She stayed forward for a second or so and you could see that her tail was off to one side. It was a textbook mating :-) Now I feel certain that these two will produce! Who would think they would even try to mate in this rain and wind? We just had a 5 minute power failure...the wind has to be blowing at 40 miles an hour at least. It's probably worse where they are.
Mickey 04/02/05 06:11 pm If I smoked I think Id have one now !

great info Ladies :)
Cecilia 04/02/05 06:13 pm Oh Mickey..You gave me a good laugh with that one :-)
karen 04/03/05 10:04 am Cecelia thanks for the great info ... I was hoping you would turn to Poole to answer Melanies question. I have yet to see any mating but if I do I will know what to look for ... I do hope this pair is successful for all of us. I have read that many young osprey couples are just "housekeeping" the first year and could see this couple in that situation.
Marie 04/03/05 10:58 pm My hunch is if these two young ospreys are really mating in ernest now, we should see eggs soon, for it takes roughly for the entire process of OVULATION through egg laying about 41 hours in a Rock Pigeon and only 24 hrs in a chicken. Perhaps for Ospreys it might take the former amount of time. If it takes as many as ???160 matings( a biologist suggested this recently) to form a clutch of eggs then we will have more matings in camera view to observe from our Dennis and Betty 2005
Marie 04/03/05 11:44 pm Thank you Cec for all the info from Poole's Bible on Ospreys. I for one can never get enough of this.......I would imagine that every bird has different behaviours generating different responses to certain stinulus.

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Tom Throwe
Last modified: Sat Feb 18, 2006