On this stormy day I have been working on lists of projected hatch dates for all our nests.....oh it's a big job. In my experience, here in Minnesota, Ospreys usually incubate about 39 days before the first egg hatches. I know other people, in other places, have come up with slightly different numbers. In the early days of this reintroduction, when I only had 8-10 nests to watch, I was able to check nests more frequently than I can now and we knew exactly when they began incubating and when the first signs of hatching occurred and it was most commonly on day 39. The first reintroduction in the US in Pennsylvania also came up with the same number. I do believe there can be some variation in those numbers but that is the number that I use for projecting hatch dates. The large number of nests we have now makes it impossible to get perfect dates for all nests so now I am categorizing them based upon the week that they should start hatching, rather than the day. It's a big list, but it will give me something to go on for organizing nest visits in the upcoming weeks. We still have a few nests that have not laid eggs...at least as of a few days ago. We have had Ospreys lay eggs at a shockingly late date....two years ago we had eggs laid in late May and chicks that didnt fledge until late August, and those birds and their dad stayed until early October! So we will keep checking!
We often discover new nests this time of year, and it's true this year as well. Please do let us know about any new nests, and don't assume that we know about it! I would rather hear repeated reports of nests I already know about than to miss one I don't know about! Thanks to those who have shared new nests, new sightings with us....we really rely on the birding public to help us with this huge task of monitoring all known nests in the eight county metro area ( Hennepin, Carver, Wright, Anoka, Washington, Ramsey, Dakota and Scott counties.) Thanks!
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