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Update on the Montana Osprey Study Birds


This year was a bust for both pairs of ospreys featured in The Call of the Osprey. As I wrote earlier, Harriet’s mate Ozzie died in Fall 2014. Several males came and went in the spring, but none of them worked out as a mate in time to make a family this year. However, near the end of the season, a male dubbed Hal seemed to have successfully paired up with Harriet, so we can hope that he will show up in the spring and raise a family with her.

Sometimes a tragedy provides an opportunity for new learning. Iris and Stanley, the other pair followed by webcam, lost their eggs to a nasty hailstorm too late to restart a family. The scientists wondered what would happen in these circumstances—would the birds stick around or leave? How would they spend their time? Here’s what Erick Green wrote on the Montana osprey cams Facebook page:

“In spite of Iris and Stanley losing their eggs in the wicked hail storm in May, this turned out to be a very interesting summer for them. This was the first year of Iris’ pretty long life that she has not successfully raised chicks (as long as we have been watching her). I was not sure how Iris and Stanley would behave after losing their eggs, but if anything this event seemed to strengthen the bond between them. They migrated south a couple of weeks ago, but up until then they spent a lot of time together. Stanley continued to bring fish in to Iris all summer long.

Many ospreys have considerable time to form a pair bond before they breed. Iris and Stanley did not have that time—Iris’ previous mate disappeared, and Stanley showed up late in that breeding season. They mated and laid eggs almost immediately. So this summer they had a lot of time together—just the two of them. Instead of going their own separate ways immediately, speaking anthropomorphically, they finally got to date and have a honeymoon. So their pair bond seems stronger than ever before they left. If they both survive the winter, we expect them back raring to go next spring.

Another consideration is that breeding takes a lot of energy for these birds, especially the females. By the end of a breeding season raising chicks, females typically have lost 10% or so of their body mass. So another silver lining of the hail storm may be that both Iris and Stanley probably left for their winter grounds in really good shape.”

I’m looking forward to following the adventures of these amazing birds—I’m hooked! You can catch up on more of what’s been going on at the study’s Facebook page and stay tuned for an update next week on the osprey named Rapunzel!

by Dorothy Hinshaw Patent

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