21 March 2014

Bea and Jasper are busy taking turns incubating their three eggs which were laid March 7th, 10th and 13th. Osprey usually lay two to four eggs, one to three days apart. Both the male and female incubate the eggs, which hatch after approximately 40 days. Because incubation starts when the first egg is laid, the eggs hatch asynchronously in the order in which they were laid. Chicks that hatch first are larger and have a competitive advantage over those that are hatch later. If food becomes scarce, the smaller chicks are less successful in competing for food, and often die. This decrease in the number of chicks in the nest makes food more available to the surviving chicks, and increases their likelihood of survival. This process, common in raptors, is called brood reduction. The past three seasons Bea and Jasper's first egg hatched after thirty nine to forty days which would put the first chick hatching on April 15/16.

Both parents expend considerable effort protecting the nest from intruders, including other ospreys and potential predators. Yesterday we had another osprey attempting to land on the platform. Both parents fended off the intruder. Ospreys are vulnerable to predation from aerial predators, such as owls and eagles . In North America, Bald eagles and great horned owls are known predators of osprey nestlings and (occasionally) adults. The speckled appearance of osprey chicks camouflages them in the nest and may be an adaptation to minimize predation by diurnal avian predators like the bald eagle. Raccoons, snakes and other climbing animals are also suspected predators of osprey eggs and nestlings.
(Poole, 1989; Poole, et al., 2002)

10 comments:

carol mullins said...

Close to having an Easter hatchling!

birdgirl said...

We possibly can have an Easter hatchling. First on April 16, second on April 18, third on April 20--Easter! We'll have to call that one the Bunny! :-)

Vivian

Anonymous said...

15:58 at the nest (Sat)
Eggs have been alone for over 20 min. and several times a Osprey on the nest but not on the eggs.
Troubles/drama at the nest (?)

Beth/Oh

birdgirl said...

So glad to see that Bea is on the nest now cuddling with her precious three eggs!!

Vivian

Anonymous said...

Houston-we have a problem :(
One egg looks broken...

Beth/Oh

birdgirl said...

A blackbird seemed to be poking around the eggs, then an Osprey came, the blackbird flew away, the Osprey -- it could have been Bea -- stayed for about 5 seconds then flew off. It's hard to tell, but one of the eggs doesn't look right. Hopefully the Moderator will get some closeups.

Vivian

Anonymous said...

I am really concerned about Bea and Jasper seeming to have abandoned the nest....what is happening...advise

birdgirl said...

I think this is Bea back on the eggs. I didn't see her move the broken one away, so guess she's on all three. Earlier, about 30 minutes ago, she came to the nest, got close to the eggs, then looked up and around and started flying just above the nest. Jasper (I think) was there earlier with a fish while Bea was away. He stayed just a few minutes, did not get close to the eggs, then flew away with the fish. Hoping all is well now.

Vivian

birdgirl said...

This morning Bea is on the nest, but it looks like she might have pushed the "broken" egg out of the nest bowl. I'm anxious for the Moderator to take a close look and let us know. Thanks.

Vivian

Sam said...

Watched the action Saturday. Beth reported no one was on the nest at about 4:00. we watched and saw a crow come in and destroy one egg. There were a number of crows and other birds who would fly in and perch and the ospreys couldn't seem to settle in on the nest. We figured something was going on above and drove over to see. There was an absolute aerial dogfight with another osprey.Although beautiful to watch we were very concerned about the nest we continued to watch until late evening. Bea seemed to finally settle down about dark. We hope the remaining eggs were not exposed too long.