Richard and Diane Van Vleck Personal Pages
The Home Habitat

2016 Nest Box Season

American Kestrel

Falco Sparverius

Tower nest box
4/10 checked tower cam video  - female in box incubating.
4/23 checked tower cam – female flushes – 5 eggs.
5/9 female incubating 5 eggs
5/18 adults feeding 5 nestlings
5/22 5 nestlings growing and doing well.
6/8 began photographing kestrels at tower entrance.
6/9 First fledges
6/10 All five have fledged

 

 

 

 

Kestrel box A
3/15 Male kestrel makes many visits to box A
3/15 Pair starlings trapped in box A
3/17 Female kestrel enters box A with male for first time
Both kestrels enter box A daily, as well as starlings and male flicker
4/8 Female kestrel lays first egg in
box A
4/10 female remains in nest box at night
4/11 2nd kestrel egg. Cold weather- female incubates
4/13 3rd egg laid, 4/15 4th egg laid, 4/17 5th egg laid
5/14 kestrel hatch day
6/12 3 kestrels fledge, 6/14 4th kestrel fledges, 6/15 5th kestrel fledges

While the renewed success at both the barn and tower nests is reassuring, there is much evidence that kestrel populations in the Northeast and mid Atlantic are losing ground.  Also, it has been reported that kestrel nests located along busy roadways or near noisy human activity are prone to desertion.  Our kestrel tower is 200 feet from a busy state highway and cedar trees along the road are now as high as the tower, blocking most of the truck noise. The cause of the 2014 nesting failures in both boxes and the 2015 tower desertion are still unknown, but, given their prior success, it is unlikely that location was a factor. Many nest box trails are mounted on utility poles along highways as a matter of convenience and economy.  And, of course, pesticides, especially rodenticides are always a concern when it comes to birds of prey.

Male American kestrel at tower box
Kestrel nestling watching for adult to return with prey
Male kestrel at tower
Nestling kestrel watching for adult's return with prey
Fledgling from box A, now confused in wagon shed
Observation blind at the tower
A fledgling kestrel from box A
The photo blind at the kestrel tower
Female American kestrel at tower nest
The tower blind
Kestrel female at the tower
The tower blind

Kestrel population decline in much of northeastern North America, including the mid-Atlantic has become of concern to many, including myself. Below are a few links to recent kestrel study.

http://kestrel.peregrinefund.org/index.php?action=decline
Regional maps of kestrel population change

http://rpi-project.org/publications/GAA-08.pdf
Raptor Watch

https://www.sciencedaily.com/releases/2013/05/130510102025.htm
Kestrels nesting near human activity show elevated corticosterone levels

http://onlinelibrary.wiley.com/doi/10.1111/1365-2664.12103/full
The full paper referenced above

http://www.bioone.org/doi/pdf/10.3356/JRR-08-83.1
WHY ARE AMERICAN KESTREL (FALCO SPARVERIUS) POPULATIONS
DECLINING IN NORTH AMERICA? EVIDENCE FROM
NEST-BOX PROGRAMS

http://rpi-project.org/publications/GAA-06.pdf
The Case of the American Kestrel

http://www.bioone.org/doi/pdf/10.3356/JRR-08-14.1
Migration Monitoring Indicates Widespread Declines of
American Kestrels (Falco sparverius) in North America

2017 Kestrel Nesting
Kestrels successfully raised a brood of 4 in box A on the barn wall. The nest box was monitored continuously with a small video camera and cap box with motion detection. All visits to the box were recorded in a daily log. As usual, flickers, starlings and kestrels made frequent visits to the box before the first kestrel egg was laid. A brief summary follows.

Feb 18 – monitoring began. Female kestrel enters box for 6 minutes

Feb 19 – Male kestrel visits briefly and starlings make frequent visits
Both male and female kestrels would briefly visit the box daily and starlings would frequently visit for longer periods.

March 8 – A starling spends the night in the nest for the first time. This was repeated for the next two nights.

March 11 – The female kestrel spends the night in the box for the first time.

March 12 – The female kestrel leaves the box at 6:26 am. A male flicker enters the box for the first time. The female kestrel enters at 17:30 for the night.

March 13 – Soon after the female kestrel leaves the box at 6:13am, a starling enters. The kestrel immediately returns and the starling leaves.  This routine is now repeated almost daily. The kestrel routs the starling simply by entering the box – no contest.
However, the starlings continue to frequently enter the box.

March 21 – Starlings begin to build a nest. Kestrel not spending night in box, but still visiting daily, and occasionally finding and routing starlings.

March 28 – I removed much starling nesting material.

March 29 – Starlings rebuilding nest. I trapped one starling and removed nesting material and added fresh wood shavings. Starlings immediately begin rebuilding. Male flicker enters and begins removing starling nesting material.

April 8 – Male flicker spends most of day in box, removing starling grass and tapping.

April 10 – Male flicker returns and taps at entrance for one hour. Kestrels continue to visit daily.

April 11 – Grey squirrel entered with one pup overnight. Observed at 5:28am. The infrared illumination is out on the camera. The squirrels left soon after I removed the box cap and took a flash photo. The next day she returned for three minutes, never to return again.  I learned several weeks later that she had moved around the corner, into an inactivated starling trap, when I observed two pups peering at me from the trap entrance.   

April 12 – After squirrel visit, the flicker and kestrels make several longer visits, each appearing to think the box is theirs.

April 14 – Only male kestrel visits

April 15 – Only kestrel visits, mostly by female.

April 16 – Kestrels rule from here on.  Female makes longer visits, up to 72 minutes, then begins staying in box overnight.

April 19 – first egg layed

April 21 – second egg layed

April 23 – third egg layed

April 25 – fourth egg layed

April 27 – fifth egg layed

April 28 – male shares incubation, as in previous years

April 29 – sixth egg laid

May 23 – 10:25 first hatch, 13:41 second

hatch, 14:09 third hatch

May 24 – fourth hatch

May 25 – fifth hatch

May 27 – sixth hatch

May 30 – sixth nestling died overnight

June 8 – Smallest nestling down and malnourished. Dead juvenile bat in nest – pecked at by nestlings, one of which unsuccessfully attempts to swallow it. The bat is continually pushed about and pecked at, to no avail. Late in the day the 5th nestling appears to be dead and two of the nestlings suddenly begin to peck at it just as they would with a prey item. The second largest nestling tears into the dead nestling methodically, first at the neck and then at the belly. The female kestrel enters with prey, feeds each of the 4 remaining nestlings and then leaves without touching the dead nestling or the bat.

June 11 – The fourth chick is much smaller and less mature than the others, but quite active. He is the only male. All 4 seem to be doing fine.

June 21 – The first three nestlings fledge, leaving the one male alone in the box.

June 27 – The male fledges.

kestrel box

kestrel nestlings

American kestrel

the male kestrel about to fledge

squirrel in kestrel nest box

female kestrel with young

American kestrel nestlings

kestrel nest box

Kestrel young

American kestrel

Falco sparverius

kestrel nestlings

kestrel nest box

kestrels in nest

kestrels ready to fledge

 

2016-2017 Kestrel Nesting
2010 American kestrel nesting
2012-2015 kestrel nesting
2002-2006 kestrel nesting
2001 American kestrel nesting
Kestrel tower
The American Kestrel
More on American kestrels

2017 - Return of the Monarchs!
Purple Martin prey photos 2017
2010 - 2014 Northern flicker nestings
2014 house wren gourd use
2014 - A dramatic loss of many types of insects
barn swallow artificial nest cups
2014 barn owl nesting - prey study
A new barn swallow shelter for 2013
2010 barn owl nesting
2010 Update
2016-2017 Kestrel nestings
Starling traps
Using blinds in the home habitat
Providing perches for birds
Providing snags for wildlife
The ugly young maple
2001 - 2013 nest cams
Use of tomato cages as hunting perches by insectivorous song birds
Vultures, beetles and the resurrection of life

Species of interest in our yard - photos and articles
barn owl American kestrel purple martin barn swallow Eastern bluebird
tufted titmouse Eastern phoebe yellow shafted flicker tree swallow chimney swift
house wren big brown bat Carolina wren brown thrasher catbird
Eastern wood-pewee
cedar waxwing Northern mockingbird
Blue-gray gnatcatcher
turkey vulture
Yellow warbler Acadian flycatcher

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