The development of the nestlings is apparent not only from their rapid growth, but also from the way they have been able to weather this passing storm.
They are now able to thermoregulate and also their feather development increasingly allows them to shed the rain.
It is hard to see, but under the still thick layer of downy feathers, they should have an increasingly thick layer of body (contour) feathers.
Photos: Latest images from the nest
Mom still occasionally shelters them from the rain, but you will also see them exposed. Yesterday they spent some time snapping at raindrops. Right after the heaviest winds and rain on Saturday mom came in and immediately began feeding them as though nothing had happened.
I have received a lot of emails regarding banding the young. Most people want to know when it is going to happen so they can watch. A few people expressed concerned for the nestling's welfare and a small number of people have philosophical concerns (arguing that we should just leave them alone.
I have decided not to band them this year, but not for the reasons suggested by the folks who either fear for the safety of the nestlings or the folks who simply believe that we should leave them be on philosophical grounds. I am not going to band because I am concerned that approaching the nest from a building window will attract more of the parent's attention to what is happening behind the glass. Nesting this close to people is a dynamic situation even if the birds are familiar with the activity in the nearby offices. The local offices have been great about putting coverings over the windows to give the birds privacy and minimizing human activity in the rooms near the nests. I have decided not to do something which might increase their focus on the office windows.
That being said, I am conformable that we can enter nests and band young without doing significant harm to the nestlings. It is undoubtedly a stressful event for both the nestlings and the parents. We are after all predators in their minds even if that is not our intention. However, each year, thousands of nestlings representing a multitude of species across the United States are banded without incident as part of ongoing efforts to learn more about our bird populations. We choose the timing of the banding very carefully ensuring that the birds are old enough to take the stress but still young enough that they will not jump out of the nest prematurely. Responsible banders back off from a nest if there is any concern that the young or adults will not be able to withstand the event. Red-tail parents have tremendous fidelity to their young once they hatch, so abandonment is a very remote possibility--they are usually very close by during the entire banding process and enter the nest within minutes of the bander leaving. The bigger risk, although still small, is to the young if they are not able to withstand the stress, but by the time we enter the nest, they are pretty darn hearty. At a nest such as this one, we have an increased advantage because we can assess them remotely before we do the nest entry. Banding requires permits and is heavily regulated by the federal government.
As per the philosophical concerns, those really are a value judgment and I respect folks differing perspectives on this matter. I band peregrine falcon nestlings every season, but I always get a special thrill out of seeing a peregrine without a band---there is something very cool about a bird that has never been touched by humans, perhaps a nest that we don't even know about somewhere out on the landscape...
The argument for banding is that it provides us with important information about bird behavior and population trends. Today nearly 25% of the bird species found in North America are experiencing significant long term declines. If current trends are allowed to continue, one out of every four species on the continent could virtually disappear in the foreseeable future. Simply "leaving them alone" is not going to reverse that trend. We are going to have to ask our communities to make major changes in order to preserve our native bird populations, and the only way that people are going to be willing to make those changes is if we have the science to back-up those decisions. Whether or not we band this specific red-tail nest is irrelevant, but the nationwide effort to band and track birds has provided us with a huge amount of data on which to base management decisions.
One quick example: Biologists tracking Swainson's Hawks along their migratory routes discovered in 1996 that use of the organophosphorus insecticide, monocrotophos by farmers in Argentina to control grasshoppers was resulting in huge levels of hawk mortality. Swainson's Hawks which migrate in huge groups would come in and feed on the poisoned insects. Biologists discovered fields with literally thousands of hawk carcasses. As a result, the United States has been working cooperatively with Argentina to phase out use of this pesticide. The discovery of this problem was on made possible by banding and radio telemetry studies.