American Kestrel (PA)

Document Actions

Species: American Kestrel (Falco sparverius)
Location: Kempton, PA
Status: Four American Kestrels fledged!

	July 2 - Empty nest! Within 10 minutes of cleaning the lens (below), the last nestling fledged! It is possible that the young birds will roost (rest or sleep) in the box for the next 10-12 days. Hopefully our computers will be working and there will be enough light in the box to see them one last time!
	July 2 - Although the camera lens is covered in fecal matter, we can just barely make out the head and beak of the last nestling in the upper left hand corner. The other three nestlings fledged yesterday. For the next two weeks, the fledglings will perch closely to one another and continue to depend on their parents for food.
	June 22 - The nearly adult-sized kestrels are fully feathered and begin to develop adult-like markings. Unfortunately, the computer's modem was zapped during several severe thunderstorms and despite our efforts to replace the modem and even the computer, we were unable to record images from the last week of the nestling period.
	June 21 - Now nearly three weeks old, the female brings in whole pieces of prey and immediately departs, leaving the young to fend for themselves in the box.
	June 20 - Within a few days, the young birds will weigh as much as an adult, and prior to fledging, they will actually weigh more than an adult.
	June 19 - The last of the four banded chicks is placed back in the box. According to the staff at Hawk Mountain, there are three females and one male in the box. The aluminum leg bands are used to identify birds and promote research and conservation efforts at Hawk Mountain Sanctuary.
	June 17 - A good shot of the feathers along their backs just starting to emerge from their sheaths.
	June 16 - Females are larger, eat more, and are capable of monopolizing food deliveries. As a result, mortality appears to fall most heavily on males.
	June 15 - The walls of the nest box are littered with fecal matter from the young who typically lean forward and lift their bottoms to defecate. It is not uncommon to see the young themselves splattered with their siblings' fecal matter.
	June 14 - Judging by the amount of feathers in the box this morning, it appears the young kestrels consumed a small bird. Kestrels are often called "sparrow hawks" because of their tendency to prey on House Sparrows.
	June 13 - A close view of one of the nestlings being served a meaty morsel from the female.
	June 12 - While we have only seen the female feeding the young, it is actually a team effort by both parents. The male hunts virtually all day and may store the prey items in a spot where the female can retrieve them at will to feed to the nestlings on demand.
	June 11 - Now almost 10 days old, the nestling are able to thermoregulate (control their own body temperature), so the female will be seen in the box only to feed her four hungry nestlings.
	June 10 - Again, only four prominent bodies appear. The nestlings are now 8-9 days old, and eating voraciously. The nestling closest to the bottom of the image is seen trying to tear a bit of meat off the vole.
	June 9 - From this image, it appears that only four young remain in the nest. Siblicide (killing of siblings) or infanticide (killing of young) is not uncommon and may have occurred to the youngest nestling, in order to ensure the maximum number of healthy young.
	June 9 - Several things may be occurring in this image. Either the female is trying to feed the youngest chick, or it has died and she is consuming it herself, or it has died and she is preparing to feed it to the remaining nestlings. The images following this one appear to point to the assumption that she is consuming the nestling herself.
	June 9 - Steadily, the young nestling appears to be getting weaker and less mobile and appears practically lifeless while the four healthy chicks feed voraciously.
	June 8 - This image shows us how much smaller the younger chick (seen in the middle) is than the other four chicks. In order to survive, the smallest chick will have to become more aggressive in its eating habits.
	June 8 - Sometime in the last few days, the fifth egg hatched. Here, while the other young are actively feeding, the youngest (and markedly, smallest) chick is passively standing by.
	June 7 - Four young begging for food from mom. We are unsure as to the status of the fifth egg. It may still be in the nest, removed from the nest, or hatched. Once we have a better camera angle, we should know better what happened to the last egg.
	June 6 - While the female is busy feeding the hungry nestlings, the male is continuously hunting for prey items. This is a critical time for the entire kestrel family as the male is more vulnerable to predation, the young birds can not regulate their own body temperatures, and the female needs to be constantly brooding the young for the first ten days or so.
	June 5 - The fifth egg to the left of the nestlings, is still in the nest. There is a good chance it will not hatch.
	June 4 - The female tends to the nestlings, whose faces are pink in color. The top photo shows one of the nestlings begging. Since the eggs began hatching, there has been a steady supply of voles for the female to nibble on.
	June 4 - Earlier, it appeared all five eggs hatched, but this image clearly exposes the fifth egg, which has yet to hatch. Since hatching is asynchronous (occurring over a period of days), the last egg might still hatch.
	June 4 - The power was accidentally disconnected this past weekend, resulting in missed hatch days. We believe the eggs began hatching on June 2 and continued hatching until today, where this image shows four young and one egg.
	June 1 - Female continues to incubate the eggs, due to begin hatching any time now.
	May 31 - Camera connection fixed and all five eggs still present.
	May 27 - One of the last shots of the kestrel cam before it was zapped during a thunder storm. We hope to have power restored before the eggs hatch.
	May 25 - The male preening himself as he incubates the eggs.
	May 24 - Since the cessation of egg-laying, we have not witnessed any more feeding inside the box. It may be that the birds are caching and eating their prey elsewhere.
	May 23 - A vivid shot of the male exiting the box after the female comes in to relieve him of his duties. The attentive parents have been off the eggs for no more than 15 minutes at a time.
	May 19 - The male preening himself in an unusual position as he continues to incubate the five eggs.
	May 18 - Egg temperature can be regulated by varying the length of time that a parent bird sits on them or the tightness of the "sit." If the parent senses too much heat from the eggs, they will move off in response to that.
	May 16 - The ideal incubation temperature for many birds' eggs is about human body temperature, 98.6 degrees F.
	May 15 - Both parents tending to the eggs, now almost half way through the development stage.
	May 14 - In order for proper egg development to occur, eggs require routine rotation. The female is turning the eggs, presumably to help warm eggs more evenly, and to prevent embryonic membranes from sticking to the shell.
	May 11 - The female kestrel incubates the eggs while the male sits perched on the entrance hole.
	May 10 - The female sits inside her box, exposing four of five eggs and looking out the entrance hole, always on the alert for any sign of trouble.
	May 9 - The male is sitting on the eggs as the female enters the box to relieve him of his incubation duties for a few hours. Each day, the male will incubate for a short period to provide the female with a break.
	May 9 - The female begins eating a vole in the corner of the box minutes after laying the fifth egg. At Hawk Mountain Sanctuary, a clutch of five eggs is very typical.
	May 8 - After incubating the four eggs for 20 minutes, the males is seen eating a vole that was left in the box. It is estimated that males will incubate the eggs nearly 20% of the time. Both male and female kestrels develop a brood patch.
	May 7 - Shortly after laying the fourth egg, the female is seen eating another vole that was delivered by the male early this morning.
	May 6 - A dead vole brought in by the male is visible in the lower right hand corner of the nest box. It remained there for over five hours before the female consumed it.
	May 5 - The third egg was laid today, some time before 9 am.
	May 4 - The male kestrel is seen tweaking his head in the direction of the camera. Since the laying of the second egg, the male has visited the nest box as often as the female.
	May 3 - The female exposes the second egg which was laid some time between 9:00am and 9:50. Notice the slightly more pink pigmentation of the second egg.
	May 1- Around 1:30, an hour and a half after we first observed the egg, the male (top photo) enters the box and carefully inspects the egg. In kestrels, the female incubates about 80% of the time, while the male provides her with food. During the next 40 minutes or so the female moved around inside the box inspecting her egg. She will likely lay a total of four to five eggs at one- to two-day intervals, beginning incubation after the second to last egg has been laid. If successful, the eggs will hatch in 28 to 30 days. May 1 - Given the large amount of time the female was spending in the box, we suspected that she would soon lay her first egg. Thus, we were watching her carefully as she conducted her late-morning vigil in the box on May 1. Then at exactly 12:00 noon the female moved slightly to her right, exposing her already laid egg (bottom photo)!
	April 30 - Preening is a form of feather maintenance that keeps the feathers clean and supple. In preening, a bird grasps the base of a feather with its bill, then slides the bill over the feather shaft toward the tip in a quivering motion. This action removes dirt and stale oil, and smooths the barbs so they will lock together. In this image, the female kestrel appears to be preening a primary feather on her right wing.
	April 28 - The female continues to spend several hours in the box each day during late morning. Presumably, she is hunting during the early morning hours when many potential prey animals, such as meadow voles and insects are most active, making them vulnerable targets. She spends the late morning hours resting and hopefully forming an egg.
	April 26 - The female looks to be in a precarious pose. We thought she could be laying an egg, but later images prove that to be wrong. It is unclear what she is doing in this photo.
	April 25 - American Kestrels are our smallest falcon, and are sometimes confused with Killdeer and Mourning Doves, especially in flight.
	April 23 - The female (top photo) is lacking the blue-gray wings and has barring all across the back. If she decides to accept this nesting site, she could lay eggs within the next 7-10 days. A beautiful shot of the male kestrel (bottom) in the box. Male kestrels have a rufous back and tail, and a pronounced black moustache. Males have blue-gray wings and partial barring on their backs.
	April 22 - Over the past few days, kestrels and starlings have been competing for the box. Observing the male kestrel in the box often is a good indication that he has claimed this nesting territory.
	April 21 - At Hawk Mountain, as well as many other places in North America, starlings are the kestrels main competitors for nesting sites. Below, a pair of starlings are visible in this box. A few hours later, a male kestrel (top) enters the nest box. Notice the large dark eye spots on the back of the kestrel's head. It is believed that eye spots help deter larger predators such as Cooper's Hawks from attacking kestrels from above.
	April 19 - There has been little activity in this box for the past week, but today, a European Starling has laid it's egg in the box intended for kestrels. Since starlings are a non-native species that often out compete our native cavity-nesters for nesting sites, it is legal to remove their nest and eggs from nest boxes.
	April 11 - Our first images of American Kestrels in the box! At about 7:30 this morning a male kestrel (bottom) enters the box. About an hour later, a European Starling (center) inspects the box and within 15 minutes of the starling visit, a female kestrel (top) enters the nest box. Shortly thereafter, a depression in the wood chips is visible and probably created by the kestrels who prefer to lay their eggs on the bare wood floor of the box. This is a good sign that the kestrels may nest in the box.

Sections

Personal tools

Learn More, Get Involved!

American Kestrel (PA)

Document Actions

Hosted by