There was a Ruby-throated Hummingbird in the northwestern alcove and a stunned and trapped Painted Bunting at the south entrance. The Painted Bunting was able to perch on its own and all signs this morning would indicate it recovered and moved on.
This AHY female Painted Bunting in post-breeding condition (dried-up brood patch) met her end at the main north entrance, and was partially obscured in some bushes. This is why I don’t just check the ground; I look everywhere a bird body could end up.
Two migrants to kick off the second week of July is not what I’d call a good sign. So far, I’ve already documented 23 casualties in 2019.
Painted Bunting is the 3rd most abundant casualty on my list (26 individuals over 10 years). Only Ruby-throated Hummingbird (34) and Lincoln’s Sparrow (51) have been more often found at this site.
Well, here we go. Today marks the end of my 9th year conducting spring/summer monitoring for window-killed birds at the Noble Research Center. Tomorrow I begin year 10. Ten years of near daily monitoring of window-killed birds. Here’s a quick 9-year wrap-up:
- 40: average minimum casualties annually
- 360: total casualties (minimum)
- 64: species confirmed as fatalities
- 10: average number of days for birds to be removed/scavenged
Top ten (eleven) species most commonly encountered as casualties at this site:
- Lincoln’s Sparrow (45)
- Ruby-throated Hummingbird (29)
- Painted Bunting (24)
- Indigo Bunting (20) *tie* Grasshopper Sparrow (20)
- Mourning Dove (17)
- Clay-colored Sparrow (16)
- Nashville Warbler (14)
- Common Yellowthroat (11) *tie* Mourning Warbler (11) *tie* Song Sparrow (11)
All carcasses remain in place, and I was saddened to discover this new one: a second-year male Painted Bunting at the main north entrance.
As the molt sequences in this species defy my ability to explain in a coherent fashion, suffice it to say that this was a male Painted Bunting born in 2017. He spent his first winter somewhere in Mexico or Central America and returned to the Great Plains to attempt his first breeding season this spring & summer of 2018. Along the way, he molted some feathers, but he had not taken on the dazzling blue and scarlet and citron of an older male, i.e., one more than two years old. He looks to have been beginning that process, however: Check out the blue feathers coming in on the face and crown and the contrast between the green-edged secondaries that have grown in more recently and the dull browns of his primaries that were the set he grew while in the nest last year.
This poor guy was probably on his way to northwestern Mexico where he would take advantage of the monsoon-driven flush of productivity to give him the fuel to finally replace those primaries in August and September. Then he would head down further south to spend the actual winter before coming back here next May.
Alas, he didn’t make it – all because of a stupid window.
Though they might have come in yesterday (when I didn’t check), there were two birds in the southwestern alcove today: a Tennessee Warbler (AHY-U, fat = 2) and a Painted Bunting (SY-U <probably female>, fat = 2).
There was also a bonus at the Food and Ag Products Center: a window-killed Yellow-billed Cuckoo and a trapped Black-and-white Warbler. The warbler flew off fine as I approached.
I actually discovered it on my 8/20 survey, but this poor little bird on the 20th was already seething with maggots so I’m comfortable calling it an 8/19 casualty. This was a second year male. Check out the feather wear on his primaries. He was headed south to molt and then continue on further south.
As I’m about to head out for a conference this week, spring and summer monitoring comes to a close. I’ll begin August 2017 the 9th consecutive year of (mostly) daily monitoring for window casualties at the Noble Research Center on the campus of Oklahoma State University in Stillwater, Oklahoma, USA.
It’s been a busy spring.
Beginning Mar 1st, here’s what has turned up at the Noble Research Center.
- Indigo Bunting – 5
- Painted Bunting – 5
- Ruby-throated Hummingbird – 3
- Lincoln’s Sparrow – 2
- Mourning Dove – 2
- Nashville Warbler – 2
- Orange-crowned Warbler – 2
- Baltimore Oriole – 1
- Chipping Sparrow – 1
- Eastern Meadowlark – 1
- House Wren – 1
- Northern Parula – 1
- Tennessee Warbler – 1
- Yellow-billed Cuckoo – 1
That’s 28 individuals of 14 species, and damn, that is disheartening.
On the plus side, my commitment to checking almost every day has put me in position to save a few birds by getting them safely away from the building and taking them someplace secure to rest and recuperate for a bit. I can’t guarantee that all 6 of these survived the ordeal, but they seemed to be in good shape when I last saw them:
- Northern Cardinal
- Common Yellowthroat
- Mourning Dove
- Song Sparrow
- Yellow Warbler
- Carolina Wren
It’s mid-June and, like clockwork, I found a lady songbird today who looks to have been involved in some post-breeding dispersal. This one was a Painted Bunting, an ASY-female with a brood patch at the southeastern alcove.
At this weird building that is the Noble Research Center, I don’t find many local birds dead at the glass. There are no feeders, for example. It’s also not a spot that attracts a lot of baby birds. No, here it’s pretty obvious that migrants are the source of the great majority of the 30–40 victims here each year, with big peaks in mortality during October and May. There is another, smaller peak, however.
That third peak is “June”. For some reason, after the collisions of the northbound migrants have died down by the end of May, birds start showing up again in mid-June. These include migrants as well as local breeders like chickadees and titmice. What’s more, it’s common for these individuals to be females that have recently bred, judging from their brood patches.
Apparently, I am capturing at this site evidence of post-breeding dispersal in females. It is not clear if these birds are looking for a new mate and territory or if they are dispersing to some specific place to molt. It is also not clear if this post-breeding dispersal involves successful or unsuccessful breeding attempts. With respect to today’s bird, however, I have to assume the latter.
Painted Buntings do not arrive here until the first week or so of May. With another week or so of finding a partner, territorial jostling, etc., that means they aren’t even beginning to nest until mid-May, i.e., about 4 weeks ago. It’s possible for a pair to have raised a brood in 4 weeks I suppose, but if so it would be odd for a female to skip town with fledglings fresh out of the nest. Thus, it’s more likely that she was dispersing today following a failed breeding attempt.
May 15th was another odd one, and I’ll be glad when this pulse of window-killed migrants is passed.
On my morning survey, I found a SY male Painted Bunting at the southwestern alcove, and right in front of a treated pane. (The bird off to the left is May 12th’s Indigo Bunting.)
That’s bad enough. The building cost a Painted Bunting and the ABC bird tape apparently did not steer it away from danger.
Then I heard from Dawn Brown later in the day (~3:45 in the afternoon) that she had found and collected a Painted Bunting at the same location. When I got there moments later, the Indigo Bunting was gone (so it was removed sometime during the day on the 15th), and Dawn handed me a bag with this bird inside:
Ugh – a second dead Painted Bunting. This one was more difficult to sex but also clearly an SY bird. Note the beak damage on both individuals.
Two more young Painted Buntings had run-ins with the Noble Research Center today, but at least one survived to tell the tale.
The first bird, an SY male with fat = 2, lay dead about 10m from the main north entrance today.
Once I had him squared away in my pocket, I turned to continue my route and immediately noticed a second SY Painted Bunting. This one, a female, was stunned but pretty feisty once I picked her up.
I took her for a walk across the quad to the trees outside Cordell Hall. She screeched most of the way (a good sign!), and then I placed her in a tree to give her the “perch test”, i.e., is the bird strong/coordinated enough to perch on a branch. She was, and she proved it to me by flying strongly to a neighboring tree and perching just fine, thank you very much.
Some people find this work I do to be a be a bit morbid, and I suppose I do spend a lot of time handing tragically dead birds. But this has also put me in position to save a few dozen birds too, notably a Painted Bunting and Summer Tanager over the last week. Every one of these little birds who flies away from me (instead of falling prey to some cat prowling around the building) makes the time most worthwhile.
Today, the Painted Bunting remains in place but the Ruby-throated Hummingbird carcass is fully gone. It lasted approximately 5 days.
At the north entrance, I flushed a small, olive-green warbler with noticeably long and yellow undertail coverts. The bird bumped the glass near me, but I was able to steer it away from the building and into some ornamental trees. I was unsuccessful at relocating it after that. My best guess is that the bird is a Mourning Warbler, given size, coloration, and the long undertail coverts. The spatial distribution of collisions now looks like this:
I found a fairly degraded immature Painted Bunting today. It looks like the ants and beetles have taken their toll, and also that it was in place prior to the rain Friday night and into Saturday. I will conservatively estimate its date of collision as Friday, 17 August 2012.
As a new fall migration begins to heat up, I’m entering into my 4th year of monitoring at the Noble Research Center. This year, I will record the approximate location on the building of all casualties and trapped birds, beginning today:
Today’s casualty will sadden my nephew: he loves Painted Buntings.
I found this female on the north side of the Noble Research Center this morning. Like other recent casualties, I have no explanation for what this bird was doing at that location today. We occasionally get them here in town in early May, but it’s early July and this bird should still be on a territory somewhere. Two days ago, I found three singing males in the shrublands of the OSU “North Fields” cross country course, so it’s still breeding season for Painted Buntings. Early migration? Post-breeding dispersal? Rounding up a wandering juvenile?
Regardless of her behavior that led this female to her unfortunate demise, she did have some fat laid down (fat = 1) and a dry brood patch. I don’t have my Pyle guide on hand this morning so my assessment of her age will be tentative: ASY.
Update: On the advice of a veritable zen master when it comes to passerine molt, this bird is now correctly aged as SY. Thank you Bob Mulvihill for pointing out the molt limit in the top photo: the distal alula covert is an original, issued to this bird when it fledged some time during the summer of 2011.
On August 20th, I completed a full year of regular surveys for window-killed birds at the Noble Research Center. Here are some vital statistics for August 20 2009–August 20 2010:
I conducted (occasionally with help from assistants like Danielle Benson) 153 surveys over the full year of monitoring. This equates to an average of 2.39 days between surveys.
Coverage was irregular throughout the year. For example I did no monitoring in January 2010. For this reason, analysis of casualties by season must be viewed through the lens of dissimilarities in sampling effort among the seasons. I defined sampling effort as the number of surveys per days in a given season. I defined seasons as follows: Dec. 1–Mar. 20 (110 days) = “winter,” Mar. 21–May 20 (61 d) = “spring,” May 21–Aug. 19 (91 d) = “summer,” and Aug. 20–Nov. 30 (102 d) = “autumn.” The 11 winter surveys provided an effort of 0.10. This approximates 10 days on average between surveys. Effort indices were 0.87 for spring (53 surveys in 61 days), 0.44 for summer, and 0.48 for autumn. Thus effort was most consistent during spring with near daily surveys.
I recorded window strike mortality for 38 individuals of 22 different species over the year of monitoring. This rate of collision mortality places the NRC on par with other high-mortality buildings referenced in Klem 1990 and O’Connell 2001.
Of the 38 casualties, 5 were “local” (i.e., recently-fledged offspring of local breeders), 5 were “hatch year” birds (i.e., “immature”, or birds < 1 yr. old), and 28 were adults or of undetermined age.
Of the the 38 casualties, 8 were identifiable as male, 5 as female, and 25 were of undetermined sex.
As in O’Connell 2001, Neotropical migrants in passage comprised the greatest percentage of individuals among all casualties. The birds dying at the NRC are not local residents that commonly occur in the OSU campus. These are transient individuals traveling long distances that just happen to meet their end here. (Note that the number of resident individuals among the casualties is inflated by the fact that 5 of the 7 casualties were recently fledged mourning doves and northern cardinals.)
On at least four occasions, I encountered live birds that appeared to be trapped near a window but were not injured from a collision. These individuals are not included in the collision data, but they may have been had I not been there to flush them away from the windows and encourage them to move along:
9/22/09: Grasshopper Sparrow and suspected Swainson’s Thrush
10/19/09: Grasshopper Sparrow
11/2/09: Two Dark-eyed Juncos
6/21/10: Carolina Wren
The scavenging rate proved to be unpredictable over the year. For example, some carcasses left in place remained visible for several weeks and were untouched during that time. Others were identifiable only from feathers left behind of a carcass that, based on the timing of my most recent survey, had been scavenged just a few hours after the bird’s unfortunate collision. Further confounding the interpretation of scavenging rates, some carcasses were scavenged but readily identifiable feathers of the carcass were left behind and still in evidence long after scavenging. For example, the Yellow-billed Cuckoo that I found on 6 June 2010 was scavenged on 15 June. As of 3 September 2010, that bird’s primaries are still readily apparent at the location where I first found it on June 10th, approximately 86 days after the bird’s death.
I found evidence of 15 scavenged carcasses over the year. Thus, out of 38 total casualties, 39% were ultimately scavenged. (Of course, I collected the majority of the carcasses I found, most of which were fresh and in excellent condition and were photographed for entries in this blog. Presumably, a high percentage of these would ultimately have been scavenged.) Two carcasses were scavenged on day 0 and three were scavenged after just one day in situ. Four were in evidence for at least 30 days; the average number of days a carcass was apparent in place was 18.6 – nearly 8 times the length of time between consecutive surveys. Thus, the regular, frequent surveys provided ample opportunity to discover carcasses before they were removed or no longer visible. In addition, the most frequent condition of freshly scavenged carcasses of warbler-sized birds was a pile of remiges cleanly sheared off near the base of the feathers. Thus, even small birds were usually left in place after scavenging; this increased the probability that I would find the carcass even if it had been scavenged. Nonetheless, it is likely that at least some individuals were scavenged and removed from the site before I could document the casualty, so mortality rates calculated from my surveys must be viewed as underestimates of actual mortality.
The following table lists all the species found as window collision casualties at the Noble Research Center, 8/20 2009–8/20 2010:
Common Yellowthroat 5
Mourning Dove 5
Lincoln’s Sparrow 4
Black-and-White Warbler 3
Grasshopper Sparrow 3
Painted Bunting 2
Mourning Warbler 1
Gray Catbird 1
Wilson’s Warbler 1
Canada Warbler 1
Indigo Bunting 1
Orange-crowned Warbler 1
Song Sparrow 1
Nashville Warbler 1
Dark-eyed Junco 1
Sprague’s Pipit 1
Swainson’s Thrush 1
Orchard Oriole 1
Northern Cardinal 1
Yellow-billed Cuckoo 1
Ruby-throated Hummingbird 1
Carolina Wren 1
This morning on my route to check for casualties at the NRC, I found a tuft of mostly contour feathers that had been cleanly sheared from their owner: At some point in the past day or two (I didn’t check yesterday), a bird hit a window and was scavenged before I could claim it. Not far away (same side of the building, ~ 20m away), I found a primary feather from a different bird that had also been scavenged! So we had two birds hit, and both were scavenged, in the past couple of days.
I am quite confident that the tuft of contour feathers came from a PAINTED BUNTING. The edges of the feathers are green, not olive like we might see in any number of species, but clearly green. Other than parrots (of which we have no naturalized species in our area), it’s really just Painted Bunting that could have left feathers like these.
The primary feather has a warm, brown edge to it – almost rusty. Given its size and color, likely candidates include Great Crested Flycatcher or one of the Catharus thrushes, of which Swainson’s is moving through in numbers these days.
I had pretty well convinced myself that the primary feather came from a Swainson’s Thrush, when on 12 May I discovered a window-killed Swainson’s Thrush at another building on campus, the Kerr Residence Hall. Looks like the right size, shape, and color to me:
I found a third Swainson’s Thrush window kill at Ag Hall on Friday, 14 May. So that’s THREE Swainson’s Thrush casualties on the OSU campus in four days, all found in one rather small corner of campus.
Now there are a lot of Swainson’s Thrushes in the world, and they’ve got a broad breeding distribution across the great boreal forest of the Nearctic. But this is what I’m talking about when I say that long distance migrants face greater risk from window collision mortality that short-distance migrants and residents. In less than a week, one guy found three window-killed Swainson’s Thrushes in an area of about 6 ha in one unremarkable little corner of Oklahoma. How many were possibly killed overall this week? Considering the broad front of migration this species is using this week, is the number dozens, hundreds, thousands?