Richmond Falcon Cam

The fourth and most likely final egg was laid sometime today, March 30th. The camera’s autofocus had a temporary issue and we weren’t able to determine exactly when the egg was laid. The first clear view of four eggs was seen shortly after 6:00pm.

The female has continued to incubate although one egg doesn’t seem to tucked under her. It is likely that the female is exhausted after the labor of laying four eggs. Hopefully once she’s had a chance to rest she’ll get all of her eggs in order.

The third egg was laid sometime after 11am on Sunday, March 28th. The falcons have begun to incubate these eggs regularly, an indication that we might expect one more egg to round out this clutch. Delaying full time incubation until the clutch is almost completed ensures they hatch hatch somewhat synchronously ( hatch together although laid somewhat apart). In general, a clutch of four falcon eggs will all hatch within 24-48 hours of each other. The cold weather that returned to Richmond during the egg laying period caused the adults to incubate the 1st two eggs more frequently than normal. It will be interesting to see if this creates a more staggered (asynchronous) hatch.

The female will do most of the incubating, although the male will take regular turns as well. The adults keep the eggs warm through use of a brood patch. This is an area of the belly in which the feathers fall off (some may be plucked by the bird) and the skin thickens. This area develops a network of blood vessels that will help warm the eggs. Both adult peregrine falcons have this patch, although the female’s is more developed as she’ll do most of the incubating.

This morning found a second egg in the nest atop Riverfront Plaza in Richmond. The female took wing to hunt with the male taking a turn at egg guarding. Although we see some incubating with these early eggs - most of the time the eggs are unincubated at this point.

One question asked frequently is how can one tell the male from the female? Female falcons are generally about 1/3 larger then males, a pattern that holds true for most raptor species. There are multiple theories as to how this size difference evolved. One holds that the difference in size reduces prey competition between the male and female, for an in depth discussion of this topic check out this link.

For this pair it is even easier to tell the male and female part. The male is banded with both a numeric USGS aluminium band and a colored auxiliary band. This male was part of cooperative program (VDGIF, CCB and Dominion Virginia Power) that hacked (released) young falcons from the nearby Dominion Tower from 2000-2002. In 2002 the male paired with the female (not a part of the release program). The pair have nested together since 2003.

The first egg of the 2010 was laid sometime overnight on March 24th. A typical peregrine falcon brood consists of 4 eggs - so we’ll continue to keep a close eye on the nest. Eggs are generally laid approximately 24-48 hours apart, although this can be quite variable. The small reddish speckled eggs average a little over 2 inches long and 1 2/3 inches wide, weighing about 1 2/3 ounces. For point of comparison, the average “large” chicken egg found in the grocery store weighs about 2 ounces.

Although the female has spent some time sitting on her egg this morning, full time incubation doesn’t generally begin until the second to last (penultimate) egg is laid. This helps the eggs to hatch more closely together, reducing the disadvantage that younger chicks might face. Peregrine falcons typically incubate for 33-35 days, so we’ll watch for hatching at the end of April.

We continue to watch and hope that the falcons settle on this nest site. Yesterday the female spent much of the day perched atop the box, and this morning (3/18) spent some time scraping gravel in the nest box.

Viewers my notice that the camera is not following the falcons or zooming in on the nest box. We have observed that the falcons appear to notice and respond to camera movement. At this sensitive stage of their breeding cycle we have decided to minimize any possible disturbances. The camera is being left in a position which allows us to see the nest box, as well as the adjacent ledge and the top of the box. Once eggs have been laid and the pair is committed to the site we will resume adjusting the camera position as appropriate.

To view archived entries prior to March 18, 2010, please select from the following monthly archives:

• January 2010
• February 2010
• March 2010