May 16, 2006
Prelude to Hatching
Nest Update: We're about three days away from the possible start of hatching. The eggs look good at this point and none look prematurely broken.
As a reminder, here is our schedule assuming all eggs are fertile:
1st egg
Date laid: 4/11
Possible hatch: 5/19
2nd egg
Date laid: 4/14
Possible hatch: 5/22
3rd egg
Date laid: 4/17
Possible hatch: 5/25
4th egg
Date laid: 4/20
Possible hatch: 5/28
Keep in mind that some of the eggs might not hatch, or some might hatch earlier and even overlap, with more than one hatching in a day. The closer the chicks are in age, the better their chances for survival.
When each chick is ready to hatch, it will pierce the air sac inside the shell and start breathing air for the first time. Then it will use its egg tooth (on the tip of its beak) to chip away at the shell. As it works, the chick will make chirping noises, which the parents will be able to hear. The chick will frequently stop to rest -- since breaking free is very tiring and its lungs have to get used to fresh air -- then it will change position and continue cutting away until it has cut through the top end of the shell and is able to kick out the bottom section. This process could take 24 hours or more. Once the chick is out, it will not have to be fed right away because before it hatches, it absorbs the yolk and uses that for early nourishment. But we've seen the parents feed the young pretty quickly regardless.
Here is a wonderful photo that illustrates what two young osprey chicks look like not long after birth. You can see their egg tooth and also their small crop (for storing undigested food).
Once a chick is born, it will be small but visible on the cam image. Here are photos showing how the first chick appeared last year. Also, the chicks have a stripe down their backs, and sometimes you can see that identifying marker as well. Because the nest is out in the open, the stripes are thought to help camouflage the chicks in case a predator is flying over and looking for signs of young in the nest.
After the birth, we might see a broken eggshell in the nest. Sometimes the parents will eat this, but most times they will just remove it from the nest as leaving it there could tip off predators that new chicks are in the nest.
As is the case with raptor young, the first chick out has the advantage and will establish itself as the dominant chick. Every chick after that has a lesser chance of surviving because of sibling aggression and competition for food. But that is the way of raptor families, even though at times it seems unfair and unforgiving. Biologists often explain this reality by saying that the younger chicks are nature's way of providing "insurance" for the family in case something happens to the older chick(s).
Finally, there is one link I wanted to pass along, as it relates to nesting ospreys: Be sure to check out the website Osprey Watch, where photographer Bob Montanaro has created a photo journal of a nesting pair of ospreys living at Pelican Island National Wildlife Refuge. Pelican Island NWR was created in 1903 by Teddy Roosevelt and was America's first national wildlife refuge. The osprey couple on this site are resident ospreys in Florida -- meaning they do not migrate -- and the photographer has provided a fascinating, close-up look at the nesting and chick-raising process. He even includes stunning photos of other types of wildlife that live near the ospreys. Visit the site to see what's in store for us in the upcoming months.
Until next time,
Lisa - webmaster
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