April 13, 2006
First Egg
Nest Update: We're very excited that on Tuesday April 11, the osprey pair delivered their first egg. The parents are doing a good job of caring for it, and they continue to mate even after the delivery of the first egg.
Osprey eggs have a brownish mottled coloring, so if it looks like there is a crack on the egg, it's often just the egg markings. Also if you see the egg briefly disappear, it's often because the parents covered it with sod once they were no longer sitting on it. The sod keeps the egg warm and hides it from predators, such as crows, Great horned owls, and even eagles.
Ospreys will normally lay two to four eggs, at an interval of one to two days apart, although sometimes three days. Incubation lasts around five or six weeks, and if the eggs are fertile, they will hatch in the order they were laid.
At the cam platform, we've never had more than three eggs laid. In 2004, all three eggs hatched, but the third chick only lasted several days and then sadly perished. In 2005, we had three eggs again, but lost sight of one egg while the other two hatched. We believe the missing chick might have hatched and then died immediately, as its egg disappeared on the day it was scheduled to hatch.
Like the eagles, both osprey parents have a brood patch and both share in the incubation duties, although the mother will incubate the majority of the time (around 70%). Incubation can be a bit sporadic until the second egg arrives, but then the parents will remain on the eggs a good part of the day and night. During the evening, the female will normally do all the incubating.
Osprey eggs, which are about the same size and shape as large hen eggs, have long been admired for their unusual coloring. Noted ornithologist Arthur Cleveland Bent called osprey eggs “the handsomest of all the hawks’ eggs” due to their color variations. Unfortunately egg-collecting played a major role in the population crash of United Kingdom ospreys during the 19th and 20th centuries, and remains a problem even now, as the osprey population is starting to revive.
You can view a close-up of osprey eggs at this Random House web page -- their photos illustrate the color variations on the eggs.
Once the eggs hatch, the chicks will look like the photo to the right, showing two newborn osprey chicks (about one and two days old) from Maurice River, New Jersey. Notice the unhatched egg in the background. The photo was loaned to us by Jane Morton Galetto, the president of Citizens United to Protect the Maurice River and its Tributaries. Be sure to visit her group's website and look at their wonderful online osprey slide shows.
We thank our cam watchers for the photos they've sent in, which help us to record these wonderful moments with our growing osprey family. We'll keep an eye out for one or two more eggs over the next few days.
Until next time,
Lisa - webmaster
(contact)