January 24, 2007

First Egg

Congratulations to our proud parents! They now have one egg in the nest -- an egg that appears to have been laid early on Wednesday morning. We originally published this photo as the first shot where the egg was visible, but I just saw this photo in our gallery submissions, and there might be an egg in this one as well. Today's egg was laid about the same time as the first egg laid in the 2005 Eagle Cam season -- that egg appeared on January 25.

As a special treat, one of our cam watchers -- Cheryl Whitney -- sent in this fun QuickTime movie showing some of today's highlights on the nest. Right-click on the image below and choose "Save Target As" or "Save Link As" to download the 1.4 MB QuickTime movie. Much thanks to Cheryl!

The Egg

The female eagle was on the nest most of yesterday and all of last night. She was sitting low and looking under herself quite frequently, but we never saw an egg until this morning. In the book titled The Bald Eagle, eagle biologist Mark Stalmaster states that "Interestingly, an eagle may assume the incubation posture even when no eggs are present. This pseudoincubation is quite common, especially just prior to egg laying." So what we were seeing yesterday afternoon and last night might have been pseudoincubation, since normally it's not that hard to see the egg once it has arrived.


eagleegg.jpgIn this web log entry, I wanted to touch on some of the many egg questions that folks sent in today. First, the egg is about the size of a goose's egg and is a dull white. Bald eagle eggs are considered to be small for such a large raptor, but eaglets are reported to be the fastest growing birds in North America, so they will reach their large size quickly.

The parents will incubate the egg for approximately 32-36 days, although all of our previous eggs on the Eagle Cam have hatched on the 35th or 36th day. This would put the hatch date at around February 28. If the egg is late to hatch, then there is a chance it was infertile. An average clutch is two eggs, but sometimes there will be three (in our first year with the Eagle Cam in 2005, we had three eggs and all the chicks fledged successfully). Eggs will be laid about two to three days apart.

Both parents have a brood patch, which is a featherless area on their lower breast where the egg comes in contact with their warm blood vessels, and both parents share the duties of incubation, although the female will do it the most. The parents will turn the egg about once an hour to keep the embryo inside from sticking to the inner shell and to ensure that the entire egg is warmed evenly.

Some folks were worried about the long periods when the parents were off the egg. We've seen this behavior in the past with both our eagles and ospreys when it comes to the first egg, and we don't think it is something to be concerned about. The parents are not leaving the egg alone. In fact it is highly likely that they are watching it from nearby, because they know that to leave it alone would make it vulnerable to crows, squirrels, and other predators.

From what we've seen on our past cams, the incubation period is more constant once the second egg is laid. But it's important to remember that the eagles are acting on instinct and experience when it comes to incubation and everything else they do. They have their own judgment as to proper incubation depending on the air temperature, the sun's warmth, the feel of the egg against their breast, etc., so we have to trust their judgment when it comes to proper care of the egg. This doesn't mean that parents never make mistakes -- sometimes they do -- but when it comes to raising eaglets, they know more than we do.

egg_closeup2.jpgA couple cam watchers asked about seeing the egg photos in the Gallery -- I will update the Gallery in the next few days, as soon as I have time to go through the photos and organize them. So once I update the Gallery, everyone will be able to see the egg photos that were recently captured.

Also, sometime over the next couple weeks, I plan to hook up our VCR to the Eagle Cam monitor at the Visitor Center and record some incubation video. If I'm successful at capturing some nest action, I'll post several video clips on the website so everyone can see the eagles going through the incubation duties.

And this brings us to a common question we've received over the last week: Why doesn't the cam have streaming video? The Eagle Cam is run by the Friends of Blackwater, which is a nonprofit citizen support group that helps the refuge serve the public. Unfortunately, streaming video is very expensive and outside our current budget. We don't want to take on corporate sponsors and consequently load our cam pages with ads and flashing banners -- we prefer to focus on the birds. Also, if we did make the splurge to streaming video, we would likely have to limit how many people could watch and for how long, and that's something we don't want to do. We would rather offer our cams to anyone who wants to watch, for as long as that person wants to watch. So for now, we will be sticking with the still images. And hopefully the videos I post at different times during the season will give everyone a feel for what the eagles look like in action.

Thanks to all those who sent in photos today, and especially those brave folks who stayed up late last night and got up very early this morning to look for an egg. I apologize to those who didn't know that the computer automatically shuts down the image updating from 11pm until 3am. We do this to save on bandwidth, and normally this is not a problem since most action occurs during the day. But I understand some folks thought the image updating had frozen up. If you have questions about our setup, be sure to read our Eagle Cam Q&A. The link to this page was on our Eagle page, but now I've put it on our cam page too, where I should have had it from the start. :-)

Until next time,
Lisa - webmaster

Posted by Webmaster at January 24, 2007 07:24 PM