May 06, 2007
Another Chance for an Egg
It looks like we have a nesting season! To recap for those who are just joining us: Back on April 13 the first egg appeared in our cam platform nest, but after it arrived, neither parent seemed interested in incubating it. While I was at the Refuge that day, I saw a second female osprey harassing the resident couple (you can see a video and read more about it here).
During the day on April 14, much fighting went on between the three birds around the cam nest, and during that time the egg was pretty much ignored. Finally a group of crows came into the nest while the ospreys were gone and cracked the egg and ate its liquid contents.
Since that time, no new eggs had appeared and the couple seemed to still have an ongoing problem with the third female, since we could see cam photos where the ospreys were diving at one another. As recently as April 19, we saw three ospreys actually sitting together for a brief moment on the nest, seeming to indicate the third bird was still around. Despite this intrusive activity, our resident couple continued to build up the nest and engage in mating behavior, so we held out hope they could get the intruder to leave and get on with nesting.
Finally on the evening of May 4, we got lucky and an egg appeared. This time the couple did not ignore it but began incubation immediately. Also during this time we did not see any signs of fighting or strange ospreys sitting on the nest.
Based on what we've observed, there is a possibility that the first egg belonged to the intruding female, as that would explain why the resident pair ignored the egg in the nest. Biologists have reported that some intruding females are actually birds looking for a place to lay their egg. If the female had lost her mate or her nest, she might have been driven to find another. Or it's possible she mated with a male whose mate was late returning from migration, and once that tardy mate returned, the male moved on, leaving the first female without a nest.
We will never know the full details of what happened, but we feel forunate to finally have an egg and a pair that seems willing to take care of it. In 2005, we had an egg laid on this same date -- May 4; that was the latest we had seen an egg laid on the platform and that chick went on to hatch and fledge. If our pair is going to lay another egg, it could come on May 6 or more likely on May 7. Most of our eggs have been three days apart at the cam platform.
Right now we hope that we get two eggs, since it would be good to have one for insurance in case the first is infertile. Three eggs would be exciting, but the last chick would have to rush to prepare for migration. As it is, any eggs now are a few weeks behind the rest of the osprey nests in the region, so two eggs would probably be a better amount with this late start to the season.
For our first egg, we would expect to see hatching around June 11 or 12, since most of our cam eggs have hatched on the 38th or 39th day of incubation.
An osprey egg is about the size of a large hen's egg and can come in different shades of tan and brown, as you can see here in this photo from the Connecticut Audubon Osprey Cam nest. Osprey eggs are admired for their beauty and variety and have been called the most beautiful of hawks' eggs. Unfortunately this admiration led to massive egg stealing in places like Britain, where egg theft and speciman collecting actually made the ospreys extinct in that region for many years. Ospreys were last recorded breeding in England in 1840 and the last United Kingdom breeding pair was destroyed in Scotland in 1916. In 1954, a pair finally returned to Scotland, and since then the ospreys have slowly begun to reestablish their populations in the United Kingdom with much help from local osprey supporters who still have to guard many of the nests from egg thieves.
We wish our osprey couple the best of luck with their nesting season. We really hope we have at least one chick to watch this summer because ospreys are very entertaining and intelligent birds that bring a lot of joy to those who follow them.
Until next time,
Lisa - webmaster
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