Nature: The beauty of a red-shouldered hawk

 

The adult female red-shouldered hawk perches near her nest.

Columbus Dispatch

Nature: The beauty of a red-shouldered hawk

June 15, 2025

Before European settlement, when 95% of Ohio was blanketed in forests, red-shouldered hawks were common. But rampant deforestation that left only 10% of the state tree-covered by the early 1900s sent hawk numbers plummeting.

Ohio’s forests have rebounded, both in expanse and age. More and bigger timber means more red-shouldered hawks, even in urban Columbus and its suburbs. As the trees in our older neighborhoods, such as Clintonville and Worthington (founded in 1803), have matured, red-shoulders have moved in and are steadily increasing.

Adult birds are conspicuously barred with stripes of rich brick-red color below. The colorful underparts are set off nicely by zebra-like black-and-white barring on the upper parts.

A red-shouldered hawk chick in its nest. Its two nest mates are hunkered down.

While red-shouldered hawks don’t sing like songbirds, they do deliver a loud piercing scream. Blue jays mimic the call to perfection and use it to scatter birds at the feeder, thus eliminating the competition.

I live in Worthington, and unknowingly, I was driving nearly daily right past an active, red-shouldered hawk nest less than half a block up the street. A friend and neighbor, Mark Granger, told me about it back in early May. The nest is high in a lofty honey locust tree and easy to miss, at least from a vehicle.

I eventually introduced myself to Dave and Sara, the homeowners. You couldn’t meet two nicer people, and the suburban hawks have great landlords. The nest is nearly over their driveway, and their two boys, Caleb and Isaac, spend much time out front shooting baskets nearly under the nest.

When Shauna and I visited to get photos, I chatted with Caleb and his friend Charlie, who are quite interested in the birds. The raptors are utterly unfazed by the young hoopsters practicing below and couldn’t have selected a safer location for their nest, which is home to three chicks.

Indeed, I wonder if red-shouldered hawks sometimes intentionally choose sites with plenty of human activity. While the male is part of the nesting process during the nest-building and incubation period — even helping to incubate eggs — he largely vanishes once the chicks hatch. Thus, the female spends long periods away hunting, and the presence of people certainly would help to deter would-be predators in her absence.

Red-shouldered hawks have a varied diet: everything from snakes to frogs to small mammals.

While red-shoulders don’t generally have huge territories, this bird probably ranges as far as the nearby Olentangy River. Its streamside forests would provide plenty of prey, and the neighborhood chipmunks best beware. They are often a dietary staple. The female will rip prey into manageable pieces for the chicks.

Dave and Sara’s red-shouldered hawk chicks look to be about two weeks or so from taking their first flight. The youngsters that make it are likely to return to the same general area next year to start nests of their own, thus further increasing Franklin County’s suburban, red-shouldered hawk population.

The red-shouldered hawk longevity record is 26 years. Dave, Sara, Caleb and Isaac might be the lucky landlords of red-shouldered hawks for some time to come.

Naturalist Jim McCormac writes a column for The Dispatch on the first and third Sundays of the month. He also writes about nature at jim mccormac.blogspot.com.

A tale of two hawks

As always, click the photo to enlarge

An adult Red-shouldered Hawk (Buteo lineatus) sits on a wire in the little village of Limerick, in Jackson County, Ohio. I was here on December 29 to cover my turf for the Beaver Valley Christmas Bird Count, along with BWD (Bird Watcher's Digest) editor Jessica Vaughn. By the way, BWD is a great magazine and if you have an interest in birds, you should subscribe. Not to toot my own horn although I clearly am, but I have an article on Kankakee Sands in northwest Indiana in the current issue. It's a spectacular birding locale and I've written about Kankakee a number of times on this blog. The recent revamp and reissue of the magazine resulted in a physical size increase, which much better showcases the numerous excellent photos featured in each issue.

Anyway, we did well on the count, with 45 species, including two Eastern Phoebes. I find these tough little flycatchers about every three to five years on this count. If the weather gives them half a chance, they'll try to ride out the winter. The bird in the above photo was one of six Red-shouldered Hawks that we found, and it was sitting in clear view of an active feeder behind a church. Despite its presence, the songbirds were not overly deterred from hitting the feeders, although I'm sure they kept a close eye on the raptor. Red-shouldered Hawks routinely visit my yard, with its usually busy feeders. "My" birds react much the same. Activity carries on, the soundscape is awash with the regular calls, birds continue to hit the feeders, and bold little chickadees will fly right by the much larger raptor as it sits on the fence or a low limb of the walnut tree. The comparatively slow and cumbersome hawk would stand little chance of bagging speedy songbirds, and they know it. I must admit, Red-shouldered Hawks have a soft, rather cute appearance that befits their mellow (for a raptor) persona. Chipmunks, mice and shrews beware, though - they form a large part of Red-shouldered Hawks' diets. In warmer seasons, the raptors catch lots of amphibians and reptiles. I imagine my red-shouldered visitors are mostly watching for chipmunks and the occasional Short-tailed Shrew that dashes from cover for spilled seed.

A juvenile Cooper's Hawk perches in my backyard yesterday morning. These bird hunters are near daily visitors, and I often know when they are around without even casting eyes on one. The yard falls silent, and songbirds vanish. They know to take no foolhardy chances with a Cooper's Hawk, whose bread and butter is small birds.

Not who you would want to see looking your way, if you were a cardinal, junco, sparrow or some other little feathered fellow.

I have plenty of dense shrubby cover in the yard and that's where the birds quickly flee when the threat of a Cooper's Hawk appears. Even that won't necessarily stop attacks. On more than one occasion I have seen a hawk run into a shrubby thicket on foot - quite terrifying for the birds hiding within, I am sure!

Sometimes birds get caught unawares and find themselves out in the open when a Cooper's Hawk materializes. They will "sleek" themselves into a compressed posture and not move a muscle, sometimes for minutes. I once watched a Carolina Chickadee - normally in perpetual motion - sit utterly still for minutes as a hawk sat nearby. I imagine Cooper's Hawks are largely triggered by movement, so sitting stone still, even if relatively exposed, might permit survival.

This juvenile was quite "tame" (or naive) and allowed me to approach to about 20 feet without apparent bother. I try to keep the back windows clean for emergency photos, but generally despise shooting through extra glass. But given his (I think it was a male based on small size) youth, I figured I might try an outdoors approach. It worked and he was still sitting on the wire when I went back inside. The close approach allowed clear images of his death-dealing talons. A small bird seized in those clutches is instantly going to be maimed and not much later, dead, its fate to be plucked and eaten.

Some people who feed birds are greatly bothered by the appearance of Cooper's Hawks. I don't know why. They are magnificent animals that emit a highly palpable life force that alters the very dynamics of their surroundings. Their fierce eyes radiate predatory cunning, and the hunter will often twitch with pent up energy as it scans its surroundings, missing nothing. When the time for action arrives, the hawk is a fury of speed and motion, launching and attacking with mind-numbing quickness. It is a pinnacle of avian evolution, a logical acme of a fantastic evolutionary process.

Red-shouldered hawk in LOW light

Corning Lake in the Holden Arboretum, on a chilly, foggy morning.

I visited the amazing Holden Arboretum yesterday for a meeting, and of course threw some photography gear in the car. The 3,600+ acres of the arboretum, which is a bit to the east of Cleveland, is a goldmine of interesting subjects. Following the meeting, we headed out to snap a few photos, mostly intending to shoot landscapes. The day was perfect for that, with persistent fog misting the grounds.

Days such as this, especially as wind was nearly non-existent, are great for shooting moody landscapes. Shutter speed is inconsequential as long as one is using a tripod. The image above was made at f/16, with a 1/2 second exposure at ISO 100. Good luck hand-holding that and achieving a sharp image.

As always, click the photo to enlarge

An adult red-shouldered hawk attentively watches a garden below. There must have been a vole or some other rodent at work in the duff of the old plants. The hawk's head was on a swivel as he watched the potential prey.

I saw the raptor a little ways off, and being a big fan of this most beautiful of eastern Buteo hawks, naturally wanted to make some photos. Red-shouldered hawks tend towards the tame, especially ones that live in places with lots of people as this one does. And sure enough, the bird was not put off by my approach and largely ignored me as it fixated on the vole or shrew or whatever it was.

Fortunately I had Canon's remarkable little 100-400mm II lens already mounted on my camera, which was on the tripod. I like trying to create tight landscapes with telephotos and that was my game until the hawk surfaced.

The challenge was light. Completely overcast white skies and fog do not offer ideal bird photography conditions. If I were to shoot the bird at any sort of "typical" setting, the ISO would have been sky high. I am not a fan of enormous ISO ranges, especially if cropping of any sort will be necessary. We're talking grainy images, even with noise reduction applied in post-processing.

As it became clear that the hawk was unconcerned with me, I only had to hope it would remain in place long enough to practice some alternate photo tactics. With the gear firmly locked in place on the tripod, and at a comfortable working range from the animal, I dialed in f/11 to create sharpness throughout the subject, and set the two-second shutter delay option. Because of the awful lighting, it was necessary to go to +2.3 exposure compensation. Once focus was set - on the bird's upper breast* - I flipped the camera into Live View mode. This eliminates any internal movement from the mirror, as it's now locked up and doesn't activate. All of this gave me a shutter speed of 1/50 - too slow to handhold and expect much in the way of crisp images, even with the 100-400's stellar image stabilization. The ISO was 800 - near the upper limits of what I prefer, but okay and it was ISO that was largely driving the shutter speed that I selected.

Once all was set, it was just a matter of activating the shutter button, and hoping the bird didn't move between then and the taking of the image. It did fidget a few times, but for the vast majority of the shots it didn't. And I got something. Shooting against blah white skies won't give the pop that superb lighting conditions will, but sometimes that's all one has to work with. And not many animals will cooperate or remain immobile long enough to employ these photographic tactics, but when they do, this is a way to keep the ISO to a sane level and thus create less grainy images. I've used it on roosting owls and nesting birds in dim light, for instance. Thus, I can remain well out of their disturbance zone, and get images that can be cropped in without noise manifestation caused by high ISO.

*A minor gripe about the 100-400mm II lens is its seeming inability to focus on tiny areas with great precision. The reason that I had to focus on the hawk's upper breast is that the camera/lens combo could not auto focus on the eye. I could have tried to manually focus there, but prefer the bulletproof accuracy of auto focus, and in single-shot mode, the auditory beep that proclaims focus has been achieved. With a relatively small f/11 aperture, it wasn't a big deal, though. And I am probably spoiled by having some of Canon's larger prime telephotos. Those lens are incredible in their ability to focus in with laser-like precision on the smallest of targets, including the eye of this raptor in bad light. But the little 100-400 costs WAY less than those big primes, and one can't expect everything at that price point. And in general, the 1 to 4 is a sensational lens. I'm nitpicking here :-)

Red-shouldered hawk, fore and aft

A gorgeous adult red-shouldered hawk scans for prey from a prominent perch. I photographed this animal last Thursday in a very suburbanized area of Columbus, Ohio.

Upon arrival at a postage-stamp natural area not far from my house, about the first bird that I detected was a red-shouldered hawk. Its strident screams couldn't be missed. An instant later, it flew in with a big branch, and led me right to its nest site. The nest isn't complete, and it may be a false start, but I hope the birds keep on with construction and use it as the nest is in a great place to discreetly watch the birds' progress.

Shortly thereafter, its mate flew in and the pair promptly copulated. Branches and other factors conspired to keep me from getting a good shot of that activity, but I tried.

The red-shouldered hawk population in Ohio and surrounding regions has been on the upswing for some time. This is a forest raptor, and as our woodlands have matured, so has favorable red-shouldered hawk habitat. Their increase has been especially notable in urban and suburban areas. Many of the neighborhoods in which I see them around Columbus now have numerous trees that are near climax stage. The effect is that of an urban forest, and in spite of all the people, houses, and traffic, the hawks have moved in.

No one should complain about having this species around. Very few raptors rival a red-shouldered hawk for showiness. In my view, their presence adds much to a neighborhood, and besides, they're fun to watch. In warmer seasons, red-shouldered hawks take lots of snakes and its always interesting to watch them rise from a dive with a wriggling reptile. I'll try and keep tabs on this pair, and see if they successfully nest at this site.

PHOTOGRAPHIC NOTE: The day that I took these photos was a typical white sky winter day. The bird in the images did cooperate nicely by hunting from a perfectly exposed perch, not far off. Red-shouldered hawks often can be quite tame, and as long as the observer is quiet they'll tolerate interlopers fairly well. Anyway, with that dastardly white sky as a backdrop, I had to GREATLY increase exposure compensation, to +2.7 EV (nearly three stops). Even then, the images were still somewhat underexposed, and I had to brighten them a bit more in post-processing. The shots were made with the Canon 5D IV and 800mm f/5.6 lens, at f/5.6, 1/320, and ISO 800, in manual mode. As often is the case, ISO drove much of my settings. I really don't like going higher than 800 if possible. As the lens was wide open at f/5.6, I had nowhere to go there. I also knew I needed all that positive exposure compensation - backing that down would have reduced the need for light. But I'm not into adding huge amounts of exposure correction in post-processing as I think it leads to poorer image quality. Thus, I dialed back the shutter speed to keep the ISO in my desired range. Even though that 800mm lens is a tank, by using good tripod-mounted stabilization techniques, it's amazing how slow a shutter speed one can use and still get a sharp image.

Red-shouldered Hawks rebound

A stunning Red-shouldered Hawk, Buteo lineatus, peers curiously down at your narrator. I probably would have reacted the same, had some strange guy rolled up under my telephone pole and stuck a long cylindrical object out the sunroof. The mild-mannered raptor never even flew. It was one of nine Red-shouldered Hawks that Peter King and I found in our piece of turf for the Hocking Hills Christmas Bird Count, last Saturday.

Everyone has their faves, and when it comes to Buteo hawks, the Red-shouldered Hawk is hands-down my #1 pick. The bird in this photo was yet another that Peter and I found on the Hocking Hills CBC. It's easy to see how the "red-shouldered" label came to be.

This particular bird came coasting over the territory of a pair of Red-tailed Hawks, which quickly rose to push the interloper away. Red-taileds are easily the most numerous Buteo in Ohio, but in some regions Red-shouldereds are gaining ground fast, or have even eclipsed their rusty-tailed brethren. We had nine Red-shouldereds, and eight Red-taileds, on this bird count and the former outnumbering the latter has become the norm in our piece of the count.

This graph displays the upward surge in Red-shouldered Hawk numbers on the long-running Cincinnati Christmas Bird Count over the past three decades. There are peaks and valleys, but the general trend of increases is indisputable. Many other CBC's in Ohio would probably show a similar trend, at least in southern, eastern, and parts of central Ohio.

This wonderful Google earth map (thank you Google earth!) shows the section of Hocking County that Peter and I covered for the aforementioned bird count. Perfect Red-shouldered Hawk country. Red-shouldered Hawks are by and large forest dwellers, peaking in areas with a blend of older-growth woodlands, stream valleys, and occasional pastures. Their nighttime counterpart is the Barred Owl - if one of these species is present, the other likely is as well.

Hard as it is to believe these days, at one time forest cover in Ohio had been reduced to about 10%. All of those heavily forested Smokeyesque places, such as the Hocking Hills, Shawnee State Forest, Mohican State Forest, etc once resembled lunar landscapes. Forest-dependent animals such as the Red-shouldered Hawk did not fare well in those dark days of deforestation. As our forests recover and mature, the hawks are recolonizing the Ohio country in ever-increasing numbers. This is even true in heavily wooded urban and suburban 'scapes. Red-shouldered Hawks are not an uncommon sight in many wooded Columbus neighborhoods, for instance. They weren't there not all that long ago.

This is another piece of Christmas Bird Count data, showing the 30-year trend for Red-shouldered Hawks statewide. A good piece of news, to be sure, especially in light of numerous species that are going the other direction.

Red-shouldered Hawks nest in a most appropriate site

Photo: Bill Thompson

Bill Thompson, aka Bill of the Birds, has been photo-documenting a beautiful pair of Red-shouldered Hawks that are nesting in a huge sycamore right outside his office building in Marietta, Ohio. And where does Bill work? Well, he is editor of Bird Watcher's Digest! These birds couldn't have selected a more appropriate place to take up residence.

Bill's been posting about these birds in his blog, and you'll want to follow him. It'll be sort of like watching a nest cam, albeit a sluggish one that uses still pictures. It should be fun and educational to follow these birds as Bill documents the nesting process, and raising of the young. It'll be doubly cool because Red-shouldered Hawks are avian herpetologists - they are especially smitten with catching amphibians and reptiles, snakes included, so we should see some interesting prey items being carted to the aerie.

Follow Bill and the hawks RIGHT HERE.

Red-shouldered Hawk

Happy New Year's, everyone! I want to thank everyone who visits this blog. I've been at this, in one form or another, for a long time - before the term "blog" had been coined. My blog is - for me, anyway - a good place to share some of what I know or am learning about natural history. There is NEVER a shortage of material - if time permitted I could put something up here every day.

I'm also fortunate that a fair number of people stop by to read this blog. Over the past month, people have surfed in from 73 countries and every U.S. state except Wyoming. C'mon, Mr. Cheney, point that browser this way!

Anyway, whether I ever hear from you or not, I'm glad you find this corner of the blogosphere interesting enough to check out.

Now, I know a number of regular visitors hail from places that rarely if ever see snow, and temperatures seldom drop low enough to raise even a goosebump. The next few photos are for you.

Saturday, January 1st, the Wilds, Muskingum County, Ohio. Temperature about 22 degrees, along with strong winds. Heavy leaden skies blocked out any sunlight, making it seem even colder. We were there for the Chandlersville Christmas Bird Count, and, believe it or not, had nearly 40 species in our patch.

Today, January 2nd, on a boondock lane in the backwoods of Hocking County. Temperature: 18 degrees. Deep in this hemlock-choked hollow, blocked of any wind, things did not seem so bad, though. Plus, the Eidermobile has heated seats - a most pragmatic luxury in such conditions! I was there to participate in the Hocking Hills Christmas Bird Count, my sixth and final count of this CBC season.

Anyway, to the subject at hand. An absolutely gorgeous Red-shouldered Hawk allows me to fawn over it at close range. This is one of the world's most beautiful raptors. Adults, like the bird pictured, possess an almost impossibly ornate suite of plumage characters: bright orange-red scalloping below, black and white checkerboarding on the wings, a diminutive bright yellow bill, and a wonderful tail barred in black and white.

Nearly anyone would find this animal of interest. Even someone who had never really looked at birds before would probably be starstruck by this sort of view of a Red-shouldered Hawk. And the viewing opportunities are far more plentiful than they were just a decade or so ago in Ohio, as this raptor has been on the upswing.

This bird sailed across North High Street in downtown Worthington yesterday, right in front of my car. He kindly sat down in a tree at the intersection of High and North Street, across from the venerable Dairy Queen, where I used to go sometimes for lunch back in high school. Many thousands of people pass by this location every day.

The nearby neighborhoods have aged to the point where the trees are now of suitable size to support breeding Red-shouldered Hawks, and the star of this blog post is one half of the local pair. Red-shouldereds have increased in many other urban areas in Ohio, too.

A short vid, showing the hawk and his busy neighborhood. The bird is seemingly well acclimated to people; he allowed me to act the paparazzi a scant 50 feet or so from his tree, scarcely bothering to reward me with a so much as a sideways glance.

The graph depicts the past 40 years of Christmas Bird Count data from Ohio. It doesn't take an ornithologist to see that the story is a positive one. There are likely two factors leading to this recovery. One, the gradual purge of DDT from the environment. This pesticide had terrible impacts on raptors, and caused great declines in many species.

Two, the overall recovery of forested habitats has allowed Red-shouldered Hawks to reclaim many former breeding areas. This is very much a raptor of woodands, and suffered when deforestation was at its worst. Now, as forests are aging they are becoming suitable habitat once again. This holds true even in older heavily treed neighborhoods in urban areas. A common companion species of Red-shouldered Hawk is the Barred Owl, which shares similar haunts. The owl is also beoming a more frequent urban dweller, and many of the wooded ravines in Columbus now sport both the owl and red-shouldereds.

Red-shouldered Hawks and toxic foliage

A great paper recently was published in the esteemed Wilson Journal of Ornithology by three Ohio researchers: Cheryl Dykstra, Jeff Hays, and Melinda Simon. They've been studying red-shouldereds for years in southern Ohio, and have unearthed some fascinating behavioral traits associated with nest construction. The title of the paper is: Selection of Fresh Vegetation for Nest Lining by Red-shouldered Hawks.

Dykstra, Hays, and Simon document the preferences of the various tree foliage that these hawks, arguably our most beautiful raptors, use to rejuvenate their nests at the onset of the breeding season.

Stunning Red-shouldered Hawk, Buteo lineatus, captured for banding. Photo courtesy of Bill Bosstic.

Young hawklets in the nest, northeast Ohio. Photo courtesy of Jim Dolan.

Of the twenty species of trees documented in the Dykstra et al paper as being added to nests, one stands head and shoulders above the rest in popularity amongst the red-shouldered crowd. Black Cherry, Prunus serotina, was found in over 80% of the ninety-eight nests studied in Hamilton and Hocking counties. And to me, this cherry/red-shouldered relationship is the most interesting facet of their research.

So enamored are the hawks with cherry that they'll go out of their way to get the plant. Dykstra and company meticulously quantified all trees within reasonable reach of the nests, and cherry were only found close at hand in a bit more than half the cases. Of course, powerful flyers like Red-shouldered Hawks are not going to be overly put out flying halfway across the county if they wish, but the research does suggest they covet this foliage enough to travel out of their way to get it. The ability of these raptors to recognize the plant means that they are also adept amateur botanists: rapto-botanists, or perhaps buteoflorists.

Why? The answer surely lies in the chemical composition of Prunus serotina. The foliage is rich in toxic nasties such as hydrogen cyanide, acetone, and a natural ant-repellant, benzaldehyde. By adorning their nests with sprigs of fresh cherry, the hawks are effectively playing the part of the Orkin Man. No pesky ants for Junior Red-shouldered! Very clever, these rust-shouldered beauties.

White-marked Tussock Moth, Orgyia leucostigma. These little bags of heavily furred goo are real stunners, but I wouldn't recommend eating one. Not that you would, but I'm just sayin'. Birds probably shun them to some degree, too. In part perhaps because these tussocks feast on... Black Cherry. Just as the Red-shouldered Hawks decorate their abodes with cherry foliage for pest management purposes, an enormous number of caterpillar species chow on cherry, probably because they have evolved to process the nasty chemicals. And thus, become unpalatable themselves. Douglas Tallamy, entomologist at the University of Delaware, has found that Black Cherry supports far more species of moth and butterfly larvae (caterpillars) than any other species of tree, including oaks.

It's a war out there. Plants don't like to be eaten. So they evolve toxins to ward off the insects. Insects evolve faster, and some cope with the poisons. They win, because then birds and other predators go "ugh", make faces and spit them out when they try for a snack. And theoretically don't try again. Then along comes some superior life form, like a Red-shouldered Hawk, and figures out how to put all of this to work. Nature is perennially fascinating.

The Dykstra, Hays, and Simon paper is a short, interesting read, and for those of you not subscribed to the Wilson Journal of Ornithology, I've posted it below (sans Table 1, which wouldn't translate from the PDF file).

THE WILSON JOURNAL OF ORNITHOLOGY • Vol. 121, No. 1, January 2009

Selection of Fresh Vegetation for Nest Lining by Red-shouldered Hawks

Cheryl R. Dykstra, Jeffrey L. Hays, and Melinda M. Simon

ABSTRACT.—Red-shouldered Hawks (Buteo lineatus) typically line their nests with fresh branches of coniferous and deciduous trees. We recorded all species of green material present in 63 nests from 2003 to 2005 in suburban Cincinnati in southwestern Ohio, and in 35 nests in Hocking Hills in southeastern Ohio, United States. We identified all trees within 0.08-ha plots at 33 nest sites in southwestern Ohio and 30 in Hocking Hills. Red-shouldered Hawks in southwestern Ohio and Hocking Hills used black cherry (Prunus serotina) branches as a nest lining more frequently than expected, based on Bailey’s 95% confidence intervals. Black cherry was found in _80% of nests but present in only 57–58% of the vegetation plots, and composed only 4–5% of the trees in the forests of the study areas. White pine (Pinus strobus), red pine (P. resinosa), and eastern hemlock (Tsuga canadensis) also were used more than expected in both study areas.

Black cherry is a cyanogenic species and may provide an advantage to nesting Red-shouldered Hawks by functioning as a natural pesticide.

Received 26 February 2008. Accepted 1 July 2008.

Many raptors line their nests with fresh green vegetation consisting primarily of
branches or sprigs of trees (hereafter ‘‘greenery’’) (Preston and Beane 1993, England et al. 1997, Buehler 2000, Ferguson-Lees and Christie 2001). The purpose of the lining has
not been definitively shown. However, it has been suggested that vegetation brought to the nest might serve a signaling function, indicating the occupancy status of the nest to con-specifics and others (Newton 1979), or a nest sanitation function, covering prey remains and waste (Newton 1979).

Red-shouldered Hawks (Buteo lineatus) line their nests with branches of fresh vegetation
(Dykstra et al. 2008). They begin bringing greenery during the nest-building phase (early Feb in southern Ohio; Dykstra et al. 2008) and continue to add fresh vegetation throughout the incubation and nestling phases. Red-shouldered Hawks in southern Ohio,
United States, bring only coniferous greenery from February through mid-April, but after
leaves appear on deciduous trees, they carry both deciduous and coniferous branches to the nests (C. R. Dykstra and J. L. Hays, unpubl. data). The objective of our study was to examine if Red-shouldered Hawks selectively used particular species of green vegetation to line their nests.

METHODS
Study Areas.—We studied Red-shouldered Hawks nesting in two regions of southern
Ohio. The southwest Ohio study area (SWOH) in Hamilton, Clermont, and Warren
counties in the suburbs of Cincinnati, is composed of residences surrounded by lawns and
non-native plantings, interspersed with small areas of natural forest dominated by second-growth mixed mesophytic, oak-hickory (Quercus spp., Carya spp.) and beech-maple
(Fagus grandifolia, Acer saccharum) associations. The Hocking Hills study area (HH) in
southeastern Ohio is composed of portions of Wayne National Forest, Hocking State Forest, Zaleski State Forest, and associated private lands in Athens, Hocking, Vinton, and Perry counties. The predominant forest type is oak-hickory with plantations of white pine (Pinus strobus) and red pine (P. resinosa).

Green Vegetation Used in Nests.—Red-shouldered Hawk nest locations and breeding
areas were previously known to us (Dykstra et al. 2000, 2004). We climbed to all accessible nests containing nestlings between 4 May and 13 June, 2003–2005 to document greenery and to band nestlings. We identified all branches or sprigs of fresh green vegetation in the nests to species or species-group, and recorded the presence/absence of each species. We identified only fresh greenery; it is likely this vegetation was collected by hawks after deciduous leaves had emerged in mid-April.

Tree Species Available in the Study Areas.
We recorded tree species and diameter at breast height (dbh) of trees _8 cm dbh to provide a sample for trees available near Red-shouldered Hawk nest sites in the SWOH and HH study areas in 1997–1998 (Dykstra et al. 2000). We centered a 0.04-ha circular plot (James and Shugart 1970) on each nest tree (n _ 33 in SWOH, n _ 30 in HH) and located a paired random plot at a distance of 75–200 m in a random direction from the nest. All trees within the plots were identified and measured (Dykstra et al. 2000). We combined data from each nest plot with that from its paired random plot to create a combination vegetation plot of 0.08 ha. Nests for which we identified trees in circular plots in 1997–1998 were not the same as those where we identified green vegetation in nests in 2003–2005; however, plots and nests were well distributed throughout the same study areas. This study design necessitated a pooled statistical analysis.

Statistical Analyses.—We recorded nest lining vegetation at some breeding areas in 2 or
3 years during 2003–2005. We randomly selected 1 year of data for inclusion in the data
set for these breeding areas to avoid pseudoreplication associated with individual pairs of
birds or territories, leaving 63 independent nests in SWOH and 35 in HH. We limited our
analyses to the 10 species of greenery most commonly found in nests. We used Bailey’s
95% CI (following Boal et al. 2005) constructed following a _2 goodness-of-fit test
(with Systat 8.0). The CIs for the proportion of nests using a particular species for nest lining were compared to the proportion of vegetation plots containing at least one tree of
that species (availability). If the proportion of plots containing the species was below or
above the 95% CI, we considered the nesting Red-shouldered Hawks had used that species as a lining more or less than expected, respectively.

We also recorded the number of trees of each species in the combination plots
and reported the sum as a percentage of total trees in all plots combined.

RESULTS
Red-shouldered Hawks in both study areas used black cherry (Prunus serotina) branches
as a nest lining more frequently than expected (Table 1). Black cherry was found in _80%
of nests but present in only 57–58% of the 0.08-ha vegetation plots (Table 1), and composed only 4–5% of the trees in the forests of the study areas (i.e., in the vegetation plots). The 95% CI assessment indicated white pine, red pine, and eastern hemlock (Tsuga canadensis) were used as nest-lining material more than expected based on availability in both SWOH and HH (Table 1). Red cedar (Juniperus virginiana) was used more than expected in SWOH. The remaining species were used in proportion to their availability or less often than expected (Table 1). The average number of species of greenery was 4.3 _ 0.2 (SE) per nest in SWOH and 3.5 _ 0.2 per nest in HH. However, the amount of greenery in nests varied widely, from a few small sprigs in the center of the nest cup to many large branches that covered the entire nest (C. R. Dykstra and J. L. Hays, unpubl. data). The average number of trees per 0.08-ha plot was 32.7 _ 2.5 in SWOH and 33.4 _ 2.5 in HH. Totals of 1,079 and 1,001 trees were identified in circular plots in SWOH and HH, respectively.

DISCUSSION
Use of Coniferous Species as Nest Lining.— Red-shouldered Hawks in both study areas apparently used red pine, white pine, and eastern hemlock more than expected based on availability. Both pines are non-native in the study areas and are nonrandomly distributed (i.e., planted primarily in plantations or in residential areas); it is possible that our vegetation plots may not have adequately sampled the distribution of pines in the habitat. Hemlock is native in the Hocking Hills region, growing primarily in north-facing ravines and along streams. It is not native to southwestern Ohio although it is planted in some residential areas. Red cedar, used more than expected in SWOH but not in HH, is native to both study areas. It is much more common in SWOH than in HH, probably because the species’ nature as a scrubby, early-colonizer makes it more suited to the developed habitats of SWOH than to the heavily forested HH. Red-shouldered Hawks also carry significant amounts of these conifers to their nests before deciduous leaf-out (C. R. Dykstra and J. L. Hays, unpubl. data).

Use of Deciduous Species as Nest Lining.
Red-shouldered Hawks in both study areas used black cherry more than expected based
on availability: more than 80% of nests we studied contained this species as a nest lining.
Black cherry, a medium-sized tree native to both study areas, is present in small numbers
in most forest types throughout the region. Black cherry is a cyanogenic species, releasing volatile hydrogen cyanide (HCN) from its leaves when they wilt or become damaged by herbivory (Conn 1979). The cyanogenesis reaction, in addition to HCN, also releases other volatile compounds such as acetone, 2-butanone and benzaldehyde, the last of which has been shown to repel ants (Formicidae) (Peterson et al. 1987). We suggest the black cherry used by Red-shouldered Hawks may provide an advantage to the nesting birds by functioning as a bactericide, insecticide, or insect repellent. Clark (1991) suggests that greenery some passerines add to their nests may release volatile compounds having insecticidal properties. The addition of yarrow (Achillea millefolium) to Tree Swallow (Tachycineta bicolor) nest boxes reduced flea abundance (Shutler and Campbell 2007), and removal of greenery from nests of European Starlings (Sturnus vulgaris) resulted in an increase in mite populations (Clark 1991). It would be interesting to examine the relationship between microbe and insect abundance, and presence of black cherry in hawk nests, to learn if black cherry has a positive effect on reproductive success. It would also be interesting to learn if Red-shouldered Hawks in other regions selectively line their nests with black cherry or any other species.

ACKNOWLEDGMENTS
We are grateful to Ann Wegman and Sandra Stone for assistance with field work. We thank the many landowners in southwestern Ohio and Hocking Hills who allowed access to private property. D. E. Andersen kindly reviewed an earlier version of this manuscript.
This research was supported in part by RAPTOR, Inc., Martin and Julie Wiltz, Brad and Marsha Lindner, and the Ohio Biological Survey.

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