Virginia.gov

VDGIF/Norfolk Botanical Garden Eagle Cam: 02/01/2010 - 03/01/2010

The Virginia Department of Game and Inland Fisheries, in partnership with the Norfolk Botanical Garden and WVEC, is providing a rare glimpse into the life of two bald eagles and their offspring!

Thursday, February 18, 2010

“When Will They Hatch?”


Now that the eagles are settled in and incubating their three eggs - the big question is when will the eggs hatch? In addition to our knowledge about bald eagle biology, we have this pair's previous history to help guide us.

The scientific literature generally reports an incubation period of 35 days (although various authorities may list 34-38 days). Directly observing when bald eagles lay eggs and when they hatch has always been a challenge for biologists, sometimes limiting how precisely we could record events. The advent of technology such as the Eagle Cam has allowed both researchers and the public an unprecedented view of what actually happens in the nest.

We can now document when eggs have been laid and when they hatch with great accuracy (often to the minute). This will help us to better understand the nesting ecology of these birds. A table of the egg laying and hatch dates since the camera has been active is included below.

Given past history - the average time for this pairs first egg to hatch has been just over 38 days (38days 3.6 hours). This would put our first egg hatching on March 9th. The second egg has hatched after an average of 37 days 7 hours and the third has averaged 36 days 3 hours. There is a clear trend of reduced incubation times for later eggs. By ensuring that the eggs hatch closer together, the disadvantage of the youngest chick is minimized. The eagles accomplish this by delaying full time incubation of the first egg (and to a lesser degree the second). This slows development and helps reduce the difference in hatch dates. It will be interesting to see if the trend holds true this year. As the first egg was laid in a snowstorm -the adults had to begin incubating it immediately. Whether or not this will have any effect in hatch dates remains to be seen.

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Tuesday, February 09, 2010

“What's on the Menu?”

This pair has had success raising large broods of three eaglets. This requires not only that the parents be skilled and experienced hunters, but also that the habitat is a rich enough resource to support their efforts. The bald eagles at the Norfolk Botanical Garden have chosen an abundant territory - One that offers many hunting opportunities.

While the bulk of a bald eagle’s diet is typically comprised of fish - they are opportunists who will feed on a variety of prey. The eagle cam has captured this pair feeding on a variety of prey - from pigeons and gulls to muskrats. Mostly though we've seen them eat fish. On several occasions we've noted spotted seatrout a marine fish that can be found in the Chesapeake Bay as well as brackish creeks (see 2009 archive). Gizzard shad are the most common prey item that we've seen in the past. This schooling fish is plentiful in nearby Lake Whitehurst.

In the past weeks we've noted two fish that we hadn't previously identified in the nest. On the first picture you'll note the rounded body and dark speckling of a black crappie. The second shows the distinct long dark barbel (or whisker) of a channel catfish. These identifications were confirmed by Chad Boyce, VDGIF fisheries biologist for the region who also noted "That's a big crappie if it came from Lake Whitehurst". He also pointed out that these species being captured at this time of year is somewhat unusual, as they typically retreat to deeper water during the winter. These "unusual" catches demonstrate that the eagles are flexible and able to utilize whatever resources are available. For more information about the fishes of Virginia check out www.virginia.gov/wildlife/fish.

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Saturday, February 06, 2010

“Egg Number 3!”

Just as the rain and sleet of another Northeaster began to turn to snow - a third egg was laid by the bald eagles at the Norfolk Botanical Garden. Just after 12:29 pm the female laid what should be the final egg of this clutch. The video below shows some of her labor and a brief view of the eggs at 12:29:50 of the camera's time stamp.

The female is currently resting and keeping all three of her eggs warm and dry.

video

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Wednesday, February 03, 2010

“2nd Egg”

Shortly before noon today (Feb 3, 2010) a second egg was laid at the Norfolk Botanical Garden. While many bald eagles only lay two eggs at a time - this pair has a history of three egg clutches. Only time will tell if a third egg is forthcoming.

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