Yet another Mourning Warbler today. This one was in the southwestern alcove. I don’t know if it had been chasing this grasshopper and they both died at the window, but it sure did look unusual to find these two together.
The 40th casualty of 2019 indicates another unusually deadly year at the Noble Research Center on the campus of Oklahoma State University here in Stillwater, Oklahoma, USA. The fact that we’ve hit that benchmark in early September is especially disheartening. This hummingbird at the main north entrance earned the sad distinction of being number 40.
As storms rolled through overnight, I assumed I might find a casualty this morning. There were two: a completely rain-soaked female Indigo Bunting in the southwestern alcove and a completely dry and fluffy Mourning Warbler at the south entrance under the rain protection provided by the portico’s overhanging roof. The latter was an AHY male with fat = 3.
Ahead of the official official ten-year anniversary of window collision monitoring at the Noble Research Center on August 20th, here’s a recap of my very first post from 7 September, 2009.
Those were heady days, indeed.
Here are some basic things I’ve observed and learned, August 2009–July 2019.
With some occasional help when I’ve been out of town, we surveyed the perimeter of the Noble Research Center for window-collided birds 2,141 times. I’ve generally run surveys every day (usually within about two hours of sunrise) during heavy migration periods in autumn and spring, scaling back to more like weekly surveys during the dead of winter.
Including 4 unidentified passerine remains, at least 414 individuals of 67 species died in window collisions at the Noble Research Center.
The most frequently encountered casualties were:
- Lincoln’s Sparrow 51
- Ruby-throated Hummingbird 36
- Painted Bunting 26
- Indigo Bunting 23
- Grasshopper Sparrow 20
- Clay-colored Sparrow 18
- Mourning Dove 17
- Nashville Warbler 16
- Mourning Warbler 15
Tenth is a four-way tie with 11 casualties each for Common Yellowthroat, Orange-crowned Warbler, Song Sparrow, and Yellow Warbler.
The spatial distribution of those casualties looks a bit like this:
Window treatments applied to selected panes in 2016 have, evidently, not contributed to a decline in collisions.
I plan to continue my monitoring at the NRC for as long as I can, and in the next 10 years hope to appreciably reduce the mortality here.
After a bit of a slow start it did not take long to wrack up 20 casualties this spring. Today it was a “day 0” Yellow-billed Cuckoo at the main north entrance, meaning that it hit and was scavenged before I found it. Here again is a reminder of the difference between scavenging and removal: This bird was immediately scavenged, but it will likely be many weeks before all traces of its feathers are gone.
Every day there is a casualty discovered is cause for a twinge of sadness. Some are worse than others, however, especially when our personal biases are affected. My internal monologue on noticing any dead bird is a classic Midwestern ope, but today it escalated to motherf****r! as I got close enough to see what it was lying in front of a glass entry on the northwestern corner of the Noble Research Center. Yep, it was the pinnacle of avian evolution, a Louisiana Waterthrush.
I would be remiss not to mention the unusually rainy, cool spring we’ve enjoyed here in the Southern Plains, and this week flooding has turned deadly. Here in Stillwater, we topped 7″ of rain on Tuesday, with roads and schools closed. But our saturated soils didn’t result from one super storm. Check out these 30-days totals:
In fact, we’re a solid 20″ above average for the year:
This is a pattern of rainfall that often washes out waterthrush nests, built along the banks of streams. Having returned at the end of March, it could easily be the case that our local waterthrushes have attempted to nest, and been flooded out, at least three times. Perhaps a scenario like that might explain how a second-year (check out the feather wear) female (she at least attempted nesting – check out the brood patch) Louisiana Waterthrush ends up outside its territory in unfamiliar habitat to die at a window on the 23rd/24th of May? Is this a local movement to find a new territory less prone to flooding and give it another go? Is this a bird that has given up for 2019 and was on her way to molt and prepare for southbound migration while other birds are still streaming north? These intimate details of birds’ lives provide endless fascination for me and, of course, can lead to new and interesting directions for research that can help these birds better survive their forays into human-dominated landscapes.
Besides the feather wear and brood patch, there were a couple of other interesting things about this bird. It had fat in the furcular hollow! Floods don’t keep waterthrushes from foraging well, despite their threat to nests. Still, actually accumulating fat is hormonally influenced, and it strikes me as odd for a bird to accumulate fat outside of migration. This bird also showed obvious trauma to the tip of the bill, indicating a window strike at full speed. I can’t quite tell if the mark on the right pectoralis major is a contusion from collision or the beginning of the progression of brood patch loss. Many questions . . .
There’s a small alcove on a northeast corner of the Food and Agricultural Products Center across a parking lot from the Noble Research Center that often lures birds to their death. Today, it was this second year Summer Tanager.
My walk to the Noble Research Center revealed two window-killed birds outside the Food and Agricultural Products building, a male Yellow Warbler and Ruby-throated Hummingbird.
I also found remains (wingtips) of the Summer Tanager and Indigo Bunting that were scavenged from the southwestern alcove.
New casualties this morning were a SY male Painted Bunting in the southwestern alcove and a male Tennessee Warbler (9.5g, fat = 1) in the northeastern alcove.
It was a bitter milestone this morning as I encountered the 400th casualty on this project since I began regular monitoring in August of 2009.
Again, the long-term idiosyncrasies of this long-term monitoring have revealed something new. In this case, there have been 4 total Summer Tanagers I’ve recorded as window-kills since 2009. The first was on May 3rd 2013. That’s 6 years ago, and it was 4 years into the project. The last three were May 4th, May 6th, and May 11th of this year. So in one week in the tenth year of a project we’ve turned on its head what we thought we knew about Summer Tanager collision risk here.
This morning was a bit odd in that it’s rare to find window killed Summer Tanagers at the NRC, and that someone had moved yesterday’s Yellow Warbler. Now the warbler and tanager lie together at the main north entrance, and I can only assume that the tanager died very close by. (The Summer Tanager was a second-year male.)
To me, these window kills are saddest when the victim is an older individual in its prime. Case in point, consider this outstanding male Yellow Warbler from this morning that senselessly met its end at the main north entrance. Note, too how conspicuous these casualties can sometimes be. As soon as I got a glimpse of the north entrance I could tell there was a casualty there.
There were no new casualties on my survey from about 7:30 this morning, but then the sharp eyes of students Dalton Deshazer, Jake Rowland, and Corey Sage noticed this Yellow-billed Cuckoo in the southwestern alcove. (On my check the next day, the bird had been moved off the sidewalk and was much less conspicuous. It persisted until removal on May 5th.)
As a bonus, Corey Sage provided this photo of a trapped Cedar Waxwing, also at the southwestern entrance, later that afternoon.
I received a message last evening that there was a casualty at the southeastern alcove. Thanks to Thomas Hess for the heads-up and this photo from 3:37 pm on April 25:
I found it right where he said it was this morning: technically a 4/25 casualty but I’ll consider it 4/26 for my records as that is when I would’ve found it on my own. I moved the bird off to the side and it remains in place as of Monday morning, 4/29.
I haven’t analyzed this, but there have been many occasions that some unusual casualty will show up and another will appear on its heels – or on the same day. These events make me wonder about pairs migrating together or, at the very least, individuals from the same regions departing at about the same time and following similar routes. How else would we explain the 9th and 10th Orange-crowned Warblers hitting the same building less than 24 hours apart?
We had a serious cold front move through on November 11–12, dropping temperatures and a decent inch or so of snow. This was unusual in that we’ve pretty much had snowless winters for the past couple of years (a couple of ice storms and no more) and that it happened so early in the season. We were probably a week or so ahead of peak autumn color here; now all of those leaves are stuck to the trees and browning. Although brief, it was a hard freeze. Birds were caught a bit unawares too, as the results of today’s survey suggest.
First, there was a Lincoln’s Sparrow in an odd spot, along the northern exterior wall. This bird looks like it had been there for a bit, like maybe it had been buried under the snow and I had missed it.
Next was an Orange-crowned Warbler (AHY-male) in the northwest alcove.
In a corner of the main north entrance to the Noble Research Center, I encountered this mystery today:
And I’m all like:
So let’s get to work on this.
First, this wasn’t here on Nov. 3 (Saturday), I did not check yesterday (Sunday), and when I found it today (Monday, the 5th) it had already been scavenged. I count examples like these as scavenging/removal on day 0.
Okay, so there’s a feather pile and a fruit pile. The fruit pile is on top of the feathers. The fruits show no signs of digestion, other than some of them having been opened and the pits are exposed. There is a single large pit inside a small fruit that is round and black with a highly glossy finish.
After much reading, comparing, consulting, etc., I’m pretty well convinced that these are chokecherries, Prunus virginiana.
My guess? I think our bird gorged itself on chokecherries before undertaking a migratory flight that, sadly, ended at a stupid window. The scavenger burst the bulging crop of this poor bird but had no interest in the fruits (in turn, feeding my opinion on the scavenger). So the remnants of this event are a pile of feathers and a pile of chokecherries.
Ah yes – the scavenger!
Well, we know that on campus we have skunks, foxes, opossums, raccoons, and feral cats as the most likely scavengers. The most likely of those to turn up its nose at a pile of chokecherries? I’d say cat. A cat scavenger would also be pretty well supported by the clean shearing of the flight feathers from the wings, visible here:
So what’s the bird? Well it’s clearly a meadowlark, but whether Eastern or Western takes some additional work. As with the fruits, I’ve spent a lot of time reading, consulting, and comparing. Perhaps the best resource for this task was a blog post from Kevin McGowan ca. 2000. (I also couldn’t get the USFWS Feather Atlas to load.)
Everyone knows that Western Meadowlark shows a yellow malar and in Eastern Meadowlark this is whitish. Without the bird’s head this character was of no use to me, however. In fact, there were just three feathers in the pile showing any yellow at all. Two other character differences are more relevant. First, both species have white outer tail feathers, but on Eastern the outer two are fully white and the third is mostly white. On Western the white is less extensive and even the outermost feather isn’t always fully white. In addition, Western looks paler overall than does Eastern, with the pattern on its tail and in the folded wings over the back appearing lighter brown/gray with blackish stripes. On Eastern, those same areas are darker brown with thicker blackish stripes often joined at the center of the feather creating a fern-like shape instead of distinct stripes. What do you think of these?
I’m leaning toward Western Meadowlark as the original owner of these feathers.
So I’m reporting today a pile of feathers that I think was Western Meadowlark, scavenged by a mammal I think was a cat, and that the cat showed no interest in what I think was a pile of chokecherries in what I think was the crop of the meadowlark.
Challenges, thoughts, etc? I welcome any and all!
Tough week here on campus as the casualties pile up.
Today, the northeast alcove had a Lincoln’s Sparrow and the project’s first Hermit Thrush. This now make casualties confirmed for 65 species at the Noble Research Center. The main north entrance claimed a Nashville Warbler, too.
Sex was undetermined for all three, but the Nashville Warbler was probably a female. The thrush and warbler looked to be after hatch year, while the sparrow was a hatch year bird. Thrush and sparrow had some fat lain down (I marked each a “one”), but I couldn’t find any fat on the warbler.
Nashville Warbler: 8.0 g
Lincoln’s Sparrow: 15.5 g
Hermit Thrush: 27.0 g
Same window, different day, same result: a HY male Ruby-throated Hummingbird whose first trip to the Neotropics was cut short by a pane of glass in the southeastern alcove.
This was the 370th casualty and 34th Ruby-throated Hummingbird found at the Noble Research Center since August 2009. Today’s casualty puts 2018 at number 7 out of 10 worst years for casualties at the NRC, and there’re still 3 1/2 months of monitoring ahead.
This morning I found the fifth dead Mourning Warbler on campus in the past two weeks: Four (including this one on the northwest alcove) at the Noble Research Center and one incidental find just across a small parking lot from the NRC at the Food and Agricultural Products Center.
For a bit of perspective on how unusual this is, i.e., Mourning Warbler is a secretive, migratory transient in Central Oklahoma that is far more likely to be found dead at a window than live on an eBird checklist, this was the 15th Mourning Warbler casualty I’ve found at the NRC since I began surveys in August of 2009. In comparison, I’ve only found 17 casualties over the same time period of the far more abundant and year ’round resident Mourning Dove.
This one was a hatch-year bird – so just a month or two old – with fat = 1.
This Ruby-throated Hummingbird at the main north entrance is the first official fall migration casualty of 2018, a dubious honor.
Note how the window is a triple threat for migrating birds: It reflects vegetation behind, provides a pass-through illusion to the other side, and it contains a naturalistic rock garden inside visible through the glass.
In other news, the Black-and-white Warbler from 31 July was scavenged overnight, with 2–3 primaries and a single downy tuft all that remains. It lasted 9 days.
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)
Both hummingbird carcasses still in evidence. The whole bird from the southeastern alcove has been decapitated, presumably by the ants.
The tail from the southwestern alcove made things a bit more interesting by being gone. I wasn’t too surprised by that because we had storms roll through overnight that I assumed would have blown that little bit of feathers away. So I started looking around just to see if I could figure out in which crack in the bricks it ended up. I couldn’t find it, but my more intensive searching did turn up these tidbits:
Aha! So it looks like yesterday’s tail was not necessarily from a hummingbird that had been scavenged. It looks more like a lawnmower got it. It also seems to have been a HY male, Ruby-throated Hummingbird.
On 22 July, I published the following post with a methodical and detailed explanation of how I determined this window casualty to be an adult female Ruby-throated Hummingbird. On July 23rd, I received a kind message from Sheri Williamson who gently explained where I had erred in my interpretation. Other than the fact that it was 1) a Ruby-throated Hummingbird and 2) dead, I had everything else wrong! Sheri literally wrote the book on hummingbird identification, so I’m delighted to have her input and grateful for the chance to learn from her.
I have now updated this post with Sheri’s interpretation explained in this blue font. Read on, learn, and enjoy. Thank you, Sheri!
In the midst of the hottest part of summer (105 F here today with a 111 heat index), I found this poor little hummingbird in the southeast alcove of the Noble Research Center.
Okay, but what hummingbird? It’s too easy to just assume “Ruby-throated” and move on. There is no obvious rufous coloration on the back or at the base of the tail to suggest one of the Selasphorus hummingbirds, such as Rufous or Broad-tailed. The wingtips not quite reaching the tail tip does suggest Ruby-throated. (Wing chord 46.0 mm on this one.) The next most likely candidate – Black-chinned Hummingbird – has wing tips that reach beyond the tail tip. So I begin with the suggestion that it actually is a Rubythroat, but it’s time to really examine it now. (So far, so good.)
The first thing to do is figure out how old the bird is. (Right here is where I mess up, and it’s all downhill from there.) Is it a hatch-year bird, i.e., one hatched this spring/summer? If not, it’s an adult: “second-year” if I can determine that it hatched in 2016 or the more general “after hatch-year” if I can’t. So, how do we determine age on a hummingbird?
The best way is to examine the bill for “corrugations.” Baby hummingbirds aren’t born with those long, pointy beaks. They start out shorter and kind of pliable, slowly lengthening and stiffening during the first few months of life. (This bird’s bill is 16.5 mm in length.) You can see this, too – although it’s difficult with my aging eyes. If there are corrugations along something like 50–90% the length of the upper mandible (the “ramphotheca” for you Ornithology students out there), then you can be certain it’s an immature hummingbird you’re examining. Adults will show usually 0% or, sometimes up to about 10% of the bill’s length showing those corrugations. What do you think about this bird?
All right, so this bird is an adult, i.e., AHY.
Nope! It’s a hatch-year bird, and that changes everything.
My other clue should have been that there are thin, buffy edges to most of the contour feathers. This is a bird in fresh plumage. An adult female should show much more feather wear at this time of year. Bill corrugations and buffy feather edges? This little sprite started life in a nest in 2017!
All right, so this bird is an immature, i.e., HY. That means it can be pretty easily sexed. (That part is still true, thankfully!) The most obvious feature for the North American Archilochus hummingbirds is the brilliant throat patch or gorget of males. This bird doesn’t have one, although it does have 3 red feathers in the gorget area and heavy throat-spotting all over the gorget:
That red looks ruby to me, too.
Okay, a few red feathers in the throat is not that rare among females. (Actually, Sheri indicated that it is really rare.) An adult male with so little red really would be odd. (True, but the rest of this paragraph is wrong-o.)
This bird looks like it might be an adult female, Ruby-throated Hummingbird. In fact, a second-year female hummingbird would be pretty unusual with that much spotting and red in the gorget. That makes me suspect that this bird was not born in 2016 and we’ve already determined that it’s not from 2017. That would mean that the bird is at least as old as a hatch-year from 2015. In other words, hatch-year is ruled out by the bill and second-year is unlikely by the spotted gorget. Yes, this is an after hatch-year bird, but it’s more specifically an after second-year (ASY) in all likelihood.
Okay, we now know that it’s a hatch-year bird. We also know that it’s got a heavily spotted gorget and already 3 ruby-reflecting feathers. It’s a boy! Yes, I mistook a young boy for a mature woman.
What else have we got?
Okay, the 6th primary feather on Ruby-throated Hummingbird has a weirdly-shaped tip. In males, it looks like a tiny Samurai sword has sliced off the tip, leaving it with a slightly concave shape that sweeps up to a rather dramatic point on the leading edge. (Although I don’t know for sure, I’m assuming that the shape of this one feather on the wing allows the males to make some kind of a mechanical sound for display.) On females – adult females – a shadow of that shape is present, too. It’s a less dramatic sweep to a point, but the 6th primary definitely looks lopped off at its tip, just like this:
According to the information in Peter Pyle’s identification guide, the feather shape on this bird is still a good match for an adult female . . . but it also is a good match for a young male. It’s still a boy.
The tail tips of female and immature Rubythroats of both sexes are just slightly notched or even straight across. Especially on females, the outer tail feathers have broad, white tips. Adult males lack the white tips on their pointed outer tail feathers, and the tail shape ends up looking strongly notched or even slightly forked. Here’s our bird’s tail:
Checks out for female Ruby-throated Hummingbird. (But again, also checks out for an HY male.)
But wait – if this is an adult female Ruby-throated Hummingbird in latter July, then she should have at least attempted to breed over the past couple of months. That means she should show a brood patch, just like this one:
It kinda means that, but again Sheri was a font of great information. To wit, that’s not a brood patch! Evidently, hatch-year birds of both sexes have apteria (portions of skin from which no feathers are growing) on the breast and belly. Experienced hummingbird handlers know this. Me? Not so much.
When I noticed what I thought was a brood patch on this bird, it colored everything else I thought about it. “If it has a brood patch, it can’t be a hatch-year bird.” “If it has a brood patch, it can’t be a male.” “If it has a brood patch, then those wrinkles I see on its bill can’t be the corrugations of a young bird’s bill.” My bias to weighting my opinion so heavily on something I was sure to be true definitely led me down the wrong path. I needed to apply better critical thinking than I did to avoid such a gaffe.
Which means . . .
There you have it: an adult female Ruby-throated Hummingbird. She had a nest and eggs at some point in recent weeks, though I can’t tell if she was successful with it. She had left her territory and might have been engaged in some local dispersal to someplace favorable for molt. She might also have been in the midst of her fall migration and, given our hot weather for the past couple of weeks I wouldn’t blame her. Either way, and whatever else might have transpired in her life as she alternated between winters in the Neotropics and summer in North America, she is another senseless loss to a window pane in our inhospitable human landscape.
None of that is true. Instead . . .
There you have it: a young male Ruby-throated Hummingbird. He was recently out of the nest and was likely on his first foray from his natal territory. Had all gone well for him, he might have ended up in southern Mexico or Guatemala or Panama. Had he survived the winter, he would’ve packed on as much fat as possible and zoomed out over the Gulf of Mexico some evening in the hope of making it back to the US after 18 hours or so on the wing. Then he would have kept going, orienting to an area probably not too far from where he was born, and prepared for a few months of pitched battles against his rivals and aggressive wooing of the ladies.
He didn’t get the chance, however. Like nearly a billion of his feathered comrades in the US each year, he fell victim to a stupid pane of glass while passing through a human-dominated landscape that can be fraught with danger for wild birds. RIP, young lad.
Monday dawned bright but soon turned sombre when I encountered the study’s first meadowlark (61st species; presumably Eastern) at the northeastern alcove. Worse, it was a baby: HY-U. Worse still: it was alive but mortally wounded and suffering greatly. It was having spasms, was unable to hold its head up, panting heavily, and bleeding through its bill, which was bent at the tip from the collision.
This is the reality of the catastrophic but not immediately fatal injuries that millions of birds endure every year. For those of us who dedicate our time to count them, we must be prepared to come face-to-face with some of our favorite creatures sometimes in the throes of a horrible and painful death. Sometimes we are even faced with the decision to intervene and usher in a more swift and merciful death than the one being endured. So that’s how my Monday morning began: euthanasia via thoracic compression of a baby meadowlark enduring unimaginable pain and fear.
The meadowlark did not recover from its window collision today, and I’m not sure I will either.
Yesterday (Friday 4/21/17) dawned stormy after an equally stormy night. We picked up nearly 2 inches of rain (+ some hail!) and enjoyed several hours of lightning and thunder. It was dicey enough – and I busy enough – that I skipped Friday’s morning survey.
Saturday, Earth Day (!) was misty, windy, and cool but mostly dry. After a morning field trip, I checked the Noble Research Center and found the fifth Orange-crowned Warbler of the survey. (Recall, that Thursday, 4/20, produced the fourth.) It is tantalizing – and sad! – to think of two birds traveling together and dying together, especially considering that the collision took place at the same spot on the building. I don’t think, however, that this ASY, fat = 0, probable female had been in place since Thursday. She was much too dry to have lain out in the open during Friday’s deluge. So I think she really did come in overnight and if not traveling with Thursday’s male, evidently following a similar route.
Surprisingly, the 277th casualty on this project was just the 4th Orange-crowned Warbler, which is a common migrant here in central OK. This one was an ASY male with fat = 1. I first spotted him from about 80m away.
Check out this guy’s truncated rectrices, blunt-tipped primary coverts, and his pointed primaries:
The most exciting thing about him, though, is that this old guy actually had an orange crown. I’ve never seen one so orange, which makes me wonder if this fellow was closer to 10 years old than merely “ASY”. It is so sad to see such a vibrant, mature, elder statesman of a warbler cut down by something so stupid as a window. He deserved better.
The Mourning Dove was still there this morning, but it has been disturbed a bit and is now on its back.
New this morning was an unfortunate Lincoln’s Sparrow at the main north entrance to the NRC. As is so often puzzling, this was a bird that had to have been traveling south to hit the glass there even though the net movement of Lincoln’s Sparrows in April in Oklahoma is north.
This bird had 0 fat, was of indeterminate sex, and looks to be a SY. Note trauma to the bill tip indicating the point of collision.
I found this rather early fellow right in front of the doorway to the southeast alcove this morning. He’s a gorgeous, ASY male Common Yellowthroat with fat score = 1. He was dazed enough that I caught him but alert and feisty in the hand, and he perched well when I moved him to a safe spot. In addition to being one of history’s all-time great yellowthroats, he has the distinction of being the 100th “trapped” bird that I’ve been able to move or shoo away from the Noble Research Center. If even one of them recovered enough to fly on and live out its life then every one of these walks around the NRC has been worth it!
Unfortunately, something went screwy with my camera and this is the only surviving photo: