2018 Breeding Season Update: A Bird’s-eye view from inside the nest

Why do birds arrive at different times on their breeding grounds, and why are there differences in when they lay eggs, and in when those eggs hatch? Is the timing of these events genetically hardwired or are these behaviors driven by the variation in environmental conditions these birds face?


To untangle the environmental and genetic factors affecting American Kestrel phenology (the timing of life cycle events), we monitored American Kestrel presence and breeding activity in nest boxes across the United States. These 246 nest boxes across 12 Department of Defense (DoD) sites encompassed a wide geographic area where vastly different environmental conditions and genetically distinct sub-populations likely occur (Read our fall blog post to see the variety of habitats across nest box sites).

To uncover what was going on inside the nest boxes, we used a combination of in-person visits (where biologists peeked inside nest boxes to see nest contents), and remote monitoring using trail cameras in nest boxes to capture time lapse images of nest contents.

Preliminary review shows that kestrels used >40 nest boxes across eight DoD sites in the 2018 breeding season.

Map of DoD sites where nest boxes have been installed: Yakima Training Center, WA; Camp Pendleton, CA; White Sands Missile Range, NM; Fort Hood, TX; Fort Riley, KS; Eglin AFB, FL; Big Oaks National Wildlife Refuge, IN; Fort Bragg, NC; Fort Drum; NY and two sites with pre-existing nest boxes: Dugway Proving Ground, UT; and Lucky Peak; ID. Orange bird symbols represent sites where American Kestrels were present in at least one nest box in 2018. Brown house symbols represent sites where no American Kestrels were present in nest boxes.

From trail cam photos and in-person visits, we collected timing information such as: the date kestrels arrived in nestboxes, when they laid eggs, when eggs hatched, and when nestlings fledged out of the nest box.

Using real-time information from cellular cameras and from communication with DoD biologists, our BSU crew conducted trips to DoD sites with nest boxes occupied by American Kestrels. We captured adult and nestling kestrels to attach unique identifying bands, take measurements, and collect genetic samples (from feathers) and isotopic samples (from claw clippings).

From April to mid-July 2018, our BSU crew banded, measured, and took samples from ~50 American Kestrels on the breeding grounds across six DoD sites (Fort Wainwright, AK; White Sands Missile Range, NM; Camp Pendleton, CA; Yakima Training Center, WA; Fort Bragg, NC; and Fort Riley, KS). DoD biologists at Lucky Peak, Idaho and Dugway Proving Ground, Utah independently captured and sampled an additional >20 kestrels. These samples will be used to help build the American Kestrel Genoscape, and to determine which individuals remained on the breeding grounds during the winter season (residents), and which individuals ventured south (migrants).

In addition to our kestrel breeding phenology data, our nest box monitoring efforts provided all kinds of fascinating data on predation, egg infertility and abandonment, and other species’ nesting phenology. Species using nest boxes ranged from starlings to flycatchers to owls; to squirrels and hungry snakes snacking on nestling birds; to infestations of wasps, ants, and kissing bugs. Although we were grateful that nest boxes provided easy hands-on access to breeding kestrels, we soon realized that they also provided refuge for many species that you’d rather not get your hands on!

OTHERSPECIES

From top left to bottom right: Rat snake in Eglin AFB, FL nest box; gopher snake in Camp Pendleton, CA nest box; European Starling in Yakima, WA nest box; Tufted Titmouse feeding nestlings in Fort Bragg, NC nest box; Eastern Bluebird feeding nestlings in Fort Hood, TX nest box; Western Screech Owl brooding nestlings in Fort Hood, TX nest box; Great-crested Flycatcher incubating eggs in Eglin AFB, FL nest box; Red Squirrels nesting in Fort Drum, NY nest box; flying squirrel in Fort Bragg, NC nest box.

In summary, the first breeding season of the Full Cycle Phenology project has been an unbelievable success and a major learning experience! Despite dealing with frustrating camera failures, nest predation, major insect infestations, and extreme weather events on DoD sites, we have made huge strides towards better understanding the variation in kestrel breeding phenology.

Stay tuned for more updates on our research as we head into fall migration season!

Time lapse video of American Kestrel nest in Yakima Training Center, Washington (video credit: Katie Callery)


This research is supported by the U.S. Department of Defense, through the Strategic Environmental Research and Development Program (SERDP RC-2702).

Special thanks to the 19 DoD biologists and volunteers across 12 DoD sites who monitored nest boxes and provided invaluable on-the-ground help with logistics, camera troubleshooting, and species identification.

Post by-Anjolene Hunt

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Winter Update: sampling American Kestrels across their U.S. wintering range

While our genetics team at UCLA dons lab coats to analyze American Kestrel breeding feather samples and create a genoscape, the rest of our Full Cycle crew has been collecting feathers from kestrels across their U.S. wintering range. By matching the genetic signature of these wintering kestrel feathers to the markers identified from breeding kestrel feathers, we hope to be able to map individuals back to their breeding population of origin and to assess migratory connectivity.

Our first season of winter trapping was a huge success! Our crew collected feather samples from 191 kestrels from 15 states across 3 migratory flyways. We also had collaborators who contributed feathers in Oregon, Arizona, Texas, Utah, and Virginia. We sampled kestrels in agricultural fields, along forest edges, inter-mountain calderas, desert regions, and on coastal beaches across the country.

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Map showing the locations that our Full Cycle Phenology crew (red dots) and collaborators (blue dots) sampled feathers from wintering American Kestrels from November 2017-February 2018

We have learned so much in this first year about conducting research across a vast geographic area, and about how much kestrels appear to vary across their wintering range in size, plumage, diet, and habitat associations. It will be so interesting to find out how genetic differences of individuals and the conditions they face in these highly diverse environments affect migration strategy and timing of life cycle events.


Whereas during the breeding season, kestrels using nest boxes are easy to find and hand-capture inside the box, things are a bit trickier during the winter season. Birds may be less tied to a specific area, and they have to be captured using other methods. We used winter Ebird locations (where other birders have seen kestrels) in combination with Google Earth imagery to hone in on the habitat that kestrels are typically associated with, and create rough maps of potential kestrel sampling routes.

When on the ground, we scanned along trees and power lines for perching kestrels. When we spotted one close enough, but not so close as to frighten them off, we placed a Bal-Chatri trap to lure kestrels in. Once kestrels’ legs were caught in the fishing line loops of the traps, we quickly ran over to collect them up for processing.

 

A pair of kestrels perches on a power pole (left), a female kestrel flies in towards a Bal-chatri trap (center), a male kestrel stands on a trap, likely caught (right). Photo credit: Jesse Watson

We took measurements of each kestrel (e.g. wing length, weight, fat score), attached a uniquely numbered USGS leg band, took photographs for plumage comparisons, and took a few breast/belly feathers for genetic analyses before releasing the bird.

 

Photographs are taken of this striking male’s back and wing plumage (left), a feather is sampled from a female kestrel (center), view of detached contour feather (right)


Our first trip to the Gulf Coast began with a rare December snowstorm in Louisiana. This was delightful for some locals making their first snowmen, but made for terrible weather to find and capture birds. Luckily, it only lasted a few days. The rest of our trip  was filled with kestrels and beautiful scenery. Mississippi and Alabama were prime kestrel areas with lots of wide open cropland and low-use dirt roads. We even recaptured a kestrel in Mississippi that had been banded in Maine in 2016!

 

A group of turkey vultures cleans a roadkill armadillo in Mississippi (top left), a short break in the rain and snow allows us to catch this male kestrel in Louisiana (bottom left), this recaptured female wintering in Mississippi was originally banded in Maine in 2016 (center), a cotton field provides hunting grounds for this female kestrel in Alabama (right)

The Florida Keys, although beautiful, were so heavily developed and highly trafficked that it was difficult to safely set a trap, while the less developed areas of the Keys were all off-limits federal or state protected land. However, we did manage to catch kestrels near some urban green spaces like marinas and golf courses, and on some of the less inhabited Keys.

 

 A female kestrel caught along a water-lined dirt road in the Florida Keys spreads her wings (top left), one of the many alligators basking near our trapping routes (bottom left), Anjolene holds a male kestrel caught at a forest-cropland edge in the Florida panhandle (center), Jesse displays a male kestrel caught beside a marina (right)


While one crew drove the Gulf Coast, our second crew headed into the Corn Belt in the Midwest (Kansas, Nebraska, and Oklahoma). Kestrels in these wide open and sparsely populated areas seemed to be wary of people, likely not used to seeing anyone down the dirt roads where they perch.  They must have had a good prey supply of corn-fed rodents, because these kestrels were the heaviest we caught all season!

 

Aislinn and Casey hold kestrels caught near a wind farm and a copse of trees in Oklahoma


With the east coast experiencing some of the coldest weeks in history, kestrel sampling was tough and chilly work in Georgia and North Carolina. Kestrels were rarely seen, likely huddled up in trees and structures to stay warm. With perseverance and warm vests, our crew managed to capture kestrels in both states, catching their first bird outside of a peanut factory. They also recaptured a female wintering in North Carolina, that had been banded as a nestling in Massachusetts 3 years prior!

 

Casey holds a female kestrel found hunting in wet fields in North Carolina (left), Aislinn releases a male on an unusually chilly day in Georgia (right)


The Imperial Valley in California had some of the highest densities of kestrels our team had ever seen! A kestrel on every second power line pole, and empty dirt roads made for prime kestrel trapping. We were lucky to have some fantastic collaborators who have worked in this area for years, to show us all of the best spots. Our team got to see where 2/3 of our winter produce is grown, and were excited to catch a kestrel beside an Aloe field.

 

An aloe field in California provides hunting grounds for kestrels (left), and Jay holds a lightweight female kestrel in Arizona (right) 


In Washington, kestrels were plentiful in areas lined with orchards and vineyards. The team came frustratingly close to catching one beside the aptly-named Kestrel Vintners winery, but were rewarded when they recaptured another female only 10 miles from where she had been banded 4 years prior!

 

Aislinn and Casey hold a male-female pair in Washington (left), and a female kestrel exhibits strikingly dark plumage


New Mexico was dry and hot, and we had to watch our traps carefully to make sure other raptors (and roadrunners!) didn’t get caught. We caught several female-male kestrel pairs who had no quandaries coming down on a trap after seeing their mate caught. It will be interesting to find out if these birds are year-round residents, or whether they are migrants that have paired up before the breeding season.

 

A Greater Roadrunner (left) demonstrates its camoflauge abilities in the dry New Mexico fields (photo credit: Anjolene Hunt), a Harris’ hawk scopes the surroundings from a power-pole perch (top right; Photo credit-Jesse Watson), Anjolene and Jesse hold a pair of kestrels caught on the same trap (bottom right)


In Texas, kestrels were not only inland in agricultural areas, but in open wooded areas, and even along the beach near Padre Island! Along with feather sampling of our Texas kestrels, we deployed GPS satellite transmitters on three females. Our transmitters send location data remotely, so we can determine exactly where kestrels migrate and breed, and use this information to validate our genetic methods. Read more about this aspect of the project on the HawkWatch International blog.

 

Jesse releases a kestrel on the beach near Padre Island, Texas (top left), this large female displays her newly attached GPS satellite transmitter (bottom left), this kestrel shares an open wooded area with cows and horses (right)


As the southern resident kestrels start getting ready to breed, and the migratory kestrels head back to breed up north, our winter season draws to a close. Stay tuned as we head into the breeding season and start our nest box camera project across U.S. Department of Defense installations!

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Post by Anjolene Hunt

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Fall update: Nest boxes across the nation

Almost everyone is familiar with American Kestrels, even if they don’t know them by name. In the spring and summer, these flashy falcons are found in abundance: sitting atop trees, telephone poles, and fence posts across North America.

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Pictured above: A particularly spotty male American Kestrel in the Florida keys perched on a distribution pole
(photo credit: Jesse Watson)

Because the geographic range of this species is so vast, individuals living in different areas (e.g. Alaska vs. Florida) face different environmental conditions and may even be genetically distinct! These differences can affect timing of breeding and migration. For example, kestrels in Alaska will breed later and will migrate south in the fall, whereas kestrels in Florida will breed earlier and remain Florida residents over winter. With changing climate, timing of breeding and migration may be shifting, and the magnitude of this shift may vary for birds in different areas!

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American Kestrels are cavity-nesters that are known to use to artificial nest boxes, and this method makes for easy monitoring of breeding populations. So to begin assessing the genetic and environmental factors affecting the timing of kestrel breeding and migration, we set up a large-scale nest box study on Department of Defense sites across the United States.

Starting with our northernmost site in Alaska, we shipped our pre-made pine nest boxes to our site, and hopped on a plane to meet them there. Next, we headed to New York, Indiana, Kansas, North Carolina, Florida, Texas, Washington, New Mexico, and California to drill nest boxes onto trees, power poles, and other elevated structures.

Pictured above: Nest boxes await shipping in a storage locker; Aislinn displays 20 bird boxes shipped to our Florida site; and Rich, Anjolene, Aislinn, and Casey post nest boxes on sites in Indiana, Alaska, Florida, and Washington.

We saw habitat from boreal forest, to long-leaf pine, to corn-fields, coastal wetland, and arid deserts, and wildlife like alligators, roadrunners, and moose. It was amazing to think about how kestrels are found in such diverse and interesting places!

Row 1 (left to right): Alaska, New York, Kansas, Indiana, North Carolina
Row 2: Florida, Texas, Washington, California, New Mexico

Along with beautiful views, each site brought with it a different set of challenges. From muddy, slippery driving and flat tires in Alaska, to bark-too-thick-to-drill-into in North Carolina, gnarled and crooked trees in Texas and Washington, to a lack of trees all together in New Mexico. Luckily for our team we had tremendous support from our Department of Defense (DoD) partners. Project co-investigator and DoD research biologist Richard Fischer facilitated communication with partners across sites, and he and fellow DoD biologist Jacob Jung met up with us on our travels to post boxes in Indiana and Kansas. We also partnered with a number of exceptional DoD biologists on each site who provided the on-the-ground knowledge, logistical help, tools, and human-power needed to get our nest boxes posted.

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In fall 2017 our team posted 200 nest boxes within Department of Defense installations in 10 states, in addition to two states which had pre-existing nest box programs. And with that we wait…. to see if kestrels across the U.S. take to their new homes, and become part of a large-scale, full-annual study of their species.

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Above: A female American Kestrel in Idaho broods her newly hatched nestlings inside a nest box


Special thanks to our on-the-ground DoD partners:

Fort Wainwright, Alaska: Daniel Rees, Garrett Savory
Fort Drum, New York: Jeffrey Bolsinger
Big Oaks National Wildlife Refuge, Indiana: Joseph Robb
Fort Riley, Kansas: Shawn Stratton, Jeff Keating
Fort Bragg, North Carolina: Jessie Schillaci
Eglin AFB, Florida: Rodney Felix, Justin Johnson
Fort Hood, Texas: Amber Dankert, Jackelyn Ferrer-perez
Yakima Training Center, Washington: Colin Leingang, Jennifer Bader
Camp Pendleton, California: Bill Berry, Diane Walsh, Katrina Murbock, Sherri Sullivan
White Sands Missile Range, New Mexico: Patricia Cutler, Doug Burkett
Lucky Peak, Idaho: Keith Hyde
Dugway Proving Grounds, Utah: Robbie Knight

 

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Breeding season wrap-up and call for winter feathers

The 2017 American Kestrel breeding season is well behind us, and the numbers are in! This breeding season, we received feather samples from 610 American Kestrels from across the breeding range!

Collaborators from 25 states sent us feathers from kestrels in their nest boxes, trapping sites, and rehabilitation facilities.

With the samples sent off to the genetics lab at University of California, Los Angeles for analyses, we are making great strides towards understanding the genetic structure of breeding kestrel populations.

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This map shows locations where we have received feathers from American Kestrels in the breeding season (orange), migration season (yellow) and winter season (blue) from 2017 and prior years. (Not pictured: Alaska). We welcome samples from all locations, but if you work with kestrels in an areas without dots, WE NEED YOUR HELP! Please SIGN UP to contribute feathers, or see our GET INVOLVED page to find out more. 


Full annual cycle research does not slow down with the cooling temperatures, and with winter upon us, the next phase of the Full Cycle Phenology project is shaping up. By sampling kestrels during migration and overwintering, we hope to be able to map individuals back to their breeding population of origin and to assess migratory connectivity and WE NEED YOUR HELP!

If you work with wintering kestrels please consider contributing feather samples. If you aren’t on our list yet, please SIGN UP to get your sampling kit mailed to you. If you are already signed up, but need more sampling envelopes, please Contact Us .

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Spring Update: American Kestrel Genoscape

The American Kestrel breeding season is well underway and kestrel researchers, citizen scientists, and wildlife rehabbers from across the U.S. and Canada have been diligently collecting feather samples to create the American Kestrel Genoscape.

 

It has been fantastic to connect with people working with kestrels across their breeding range, and we are excited to learn more about the different breeding populations from Alaska down to Florida, and from coast to coast across the continental U.S. and Canada! In 2017, we have had 28 feather contributers sign up from 16 states, and 5 Canadian provinces, bringing our total sampling area to 24 states, and 5 provinces from 2016-2017 (see map below).

Although we have had a great show of support and feather sample contributers, we are still in need of feather samples, particularly from the Midwest (see map below). If you work with kestrels in this area, please SIGN UP to contribute feather samples. We have little information about kestrels in this region, which may use different migratory flyways and wintering locations than eastern or western populations.

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This map shows locations where we have feather sample contributers (2016: blue dots, 2017: orange dots).
We welcome samples from all locations, but if you work with kestrels in an areas without dots, WE NEED YOUR HELP! Please SIGN UP to contribute feathers, or see our GET INVOLVED page to find out more. 

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