May 17, 2004
When Chicks Enter the World
Nest Update: We should see hatching sometime in the next couple weeks. The chicks will be small, so keep a close eye on the mother. If the chicks are present, we'll see her feeding them soon after they're born.
Pic of the Week: The Pic of the Week goes to Norman Porter who captured a nice photo of the father osprey bringing another stick to the nest. The osprey parents will continue to bring material to the nest as a way to replace matter that has fallen out and also as a way to bury fish remains or other objectionable material that has piled up within the nest.
Now that we're getting close to hatching time, what can we expect to see when the big moment arrives? Before a chick makes its entry into the world, it will begin to chip away at the shell from the inside, using its egg tooth (the hardened tip of the upper beak). Below are two excellent photographs showing osprey newborns eating and resting. If you look closely at the second photo, you can see the white egg tooth on the upper beak of each of the newborn osprey chicks.
Click on the thumbnails for a larger version.
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When an osprey chick finally breaks through its egg, it will be down-covered, weak and helpless (at birth, its neck will be the strongest part of the body as it was used to drive the egg tooth through the shell). A few hours after birth, a chick's eyes will open and it will be able to take fish bits from its mother.
The oldest eggs should hatch first, and these chicks will have a distinct advantage in the family pecking order. Osprey expert Alan Poole reports that when third chicks hatch, they are 25%-30% lighter on average than older siblings and less likely to survive when food is scarce. When food is in short supply, the older chicks have been known to turn on younger, weaker siblings, pecking at the runts and sometimes even killing them or pushing them over the edge of the nest.
Author David Gessner witnessed a fatal chick attack while observing an osprey nest in the Cape Cod area, a story which he details in his book "Return of the Osprey." Although he admits he was at first angry with the mother osprey for not preventing the attack, he said he later realized that he was judging the mother by human terms and that osprey families operate differently.
As Alan Poole has pointed out, "Parents never interfere in such squabbles, apparently because it fits their interests to raise one or two well-fed young, instead of the three or four weak ones that would result if scarce food were shared equally." Ospreys have been common in the northern hemisphere for the last 10 to 15 million years, so it is safe to say that their method for raising young is beneficial for the species.
If the food supply is good in the osprey's home area, this intense competition between the chicks is not necessary. Last year was our first year with more than one chick in the cam nest. During that time, both chicks appeared well-fed and there was no outright fighting seen in the nest, thus indicating that the food supply at Blackwater Refuge was apparently adequate for the family's needs. If all three eggs are successful this year, we will see if the local food supply -- and the father's hunting skills -- are up to raising such a large family.
Until next time,
Lisa - webmaster (contact)
Submitted by Norman Porter