29 September 2019 – Lincoln’s Sparrow

A sad sign of autumn in Stillwater, Oklahoma: I found the first window-killed Lincoln’s Sparrow of the fall. I did not check yesterday (Sep. 28) but that’s probably when this collision occurred.

15 November 2018 – Orange-crowned Warbler and Lincoln’s Sparrow

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.

 

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26 October 2018 – Chipping Sparrow and trapped Lincoln’s Sparrow

Amazing that this was just the third Chipping Sparrow I’ve found in 9 years of window collision monitoring.

The Lincoln’s Sparrow was in the portico, flew west and took a sharp right, only to get re-trapped.

19 October 2018 – Lincoln’s Sparrow, plus another Lincoln’s Sparrow

I found two Lincoln’s Sparrow victims today, both in somewhat odd places. At the Noble Research Center, one met its end at the door leading out to the eastern courtyard. This might be only the 2nd or 3rd victim in the courtyard since 2009.

I also occasionally check for window collision victims at the Food and Agricultural Products Center just to the west across the parking lot and Monroe St. This morning there was a Lincoln’s Sparrow in a tiny alcove where I’ve found birds in the past. This one I noticed by looking to my right as I drove down the street this morning.

18 October 2018 – Lincoln’s Sparrow, Hermit Thrush, and Nashville Warbler

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

 

 

 

17 October 2018 – four Lincoln’s Sparrows

It was one of those tough days to be a Lincoln’s Sparrow on campus today. There were dead birds at the main north entrance and on the south portico. I examined the south portico bird which looked to be HY-U, with fat = 3. There were two more trapped Lincoln’s Sparrows I flushed from the main north entrance. They flew away strongly, showing no evidence of collision.

16 October 2018 – Lincoln’s Sparrow and a bob-tailed House Wren

My first Lincoln’s Sparrow of the year showed up at the northwestern alcove today. I do much prefer to see them alive beneath my feeders. . .

Another feathered friend was very much alive, though stunned from a collision in southeastern entrance. He looked a bit shaky when I first found him, but he was actually fairly perky and difficult to catch. As it was chilly in the shade, I took the bird to a sunny spot near my office where he could more safely and quickly recover. Checking on the bird a bit later in the day, it was still there but flying strongly and looking to be recovering.

This bird was a wren of ambiguous affinity. It’s short tail was evocative of Winter Wren, but its plumage was a better match for House Wren. The bob tail might indicate a HY bird, but I didn’t spend much time examining its plumage for aging as my main concern was to make sure it had a safe place to chill out.

31 July 2018: end of season wrap-up

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)

 

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26 April 2018 – Lincoln’s Sparrow

It was an inauspicious start to my observance of Audubon’s birthday with this poor Lincoln’s Sparrow in the northwest alcove. AHY-U, fat = 2, left in place.

7–18 October 2017 – all kinds of stuff

I’ve been behind with stacks of papers to grade, and they’ve kept me from keeping up as often as I’d prefer. During the period from October 7–18, I conducted 8 surveys, skipping Oct. 8, 14, and 15. The data from these last 11 days look a bit like this:

  • Oct. 7: HOWR
  • Oct. 9: no casualties
  • Oct. 10: no casualties
  • Oct. 11: LISP
  • Oct. 12: TUTI
  • Oct. 13: no casualties
  • Oct. 16: OCWA, SOSP, LISP, and NAWA
  • Oct. 17: no casualties
  • Oct. 18: no casualties

Just past mid-October, and we are crushing the annual mortality count right now with 55 dead birds.

Oct. 7 – I found just the third House Wren on the project.  This one ended up on a warm air outflow grate from the air conditioning unit and was quickly desiccated.

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Oct. 11 – I collected this Lincoln’s Sparrow from the south portico.

Oct. 12 – This Tufted Titmouse was a surprise in the southwestern alcove.

Oct. 16 – This was not a good day for migrants. I found an Orange-crowned Warbler at the northeast alcove, a Song Sparrow at the south portico, and a Lincoln’s Sparrow at the southwestern alcove. Shortly after completing my survey, a Nashville Warbler was turned in from a collision in the southwestern alcove.

 

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29 September 2017 – Lincoln’s Sparrow

It’s sad to realize that the real harbinger of autumn here in Stillwater is the first Lincoln’s Sparrow casualty at the Noble Research Center.

Spring/Summer 2017 was busy

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.

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Beginning Mar 1st, here’s what has turned up at the Noble Research Center.

Dead Birds

  1. Indigo Bunting – 5
  2. Painted Bunting – 5
  3. Ruby-throated Hummingbird – 3
  4. Lincoln’s Sparrow – 2
  5. Mourning Dove – 2
  6. Nashville Warbler – 2
  7. Orange-crowned Warbler – 2
  8. Baltimore Oriole – 1
  9. Chipping Sparrow – 1
  10. Eastern Meadowlark – 1
  11. House Wren – 1
  12. Northern Parula – 1
  13. Tennessee Warbler – 1
  14. 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:

  1. Northern Cardinal
  2. Common Yellowthroat
  3. Mourning Dove
  4. Song Sparrow
  5. Yellow Warbler
  6. Carolina Wren

 

 

25 April 2017 – Lincoln’s Sparrow

The main north entrance claimed a Lincoln’s Sparrow today – ASY-U and bulging with fat = 3.  (Apologies for the lousy photos.)

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13 April 2017 – Lincoln’s Sparrow

The Mourning Dove was still there this morning, but it has been disturbed a bit and is now on its back.

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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.

3 November 2016 – 2 Lincoln’s Sparrows

The south portico was the scene for the sad demise of two HY Lincoln’s Sparrows this morning. One was fat = 2 and the other was fat = 3.

19 October 2016 – Lincoln’s Sparrow and Common Yellowthroat

Flight calls abounded last night as I walked the dog at least thrice.  Those calls – little tsips! and tseeps! sounded to me like sparrows flowing from the north after three straight days of strong winds blowing from the south. A quick check of Paul Hurtado’s Nexrad radar birds page confirmed a big push in Midwest and the Plains:

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Sadly, with that push came two casualties at the Noble Research Center: a Lincoln’s Sparrow (AHY-U with fat = 2) at the southwest alcove and a Common Yellowthroat (AHY-M with fat = 2) at the northwest alcove.  (Apologies for the shaky portrait on the Yellowthroat – it looked clear on my phone.)

 

Although casualties continue to pile up in the west alcoves where I’ve treated several windows with ABC Bird Tape, it has so far appeared to be the untreated panes in those alcoves that are claiming the casualties.

13 October 2016 – trapped Lincoln’s Sparrow

Today I found a stunned Lincoln’s Sparrow on the south portico (no photo).

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The bird couldn’t fly well, but it could fly.  I decided to give it the “perch test” to determine if I should consider it to be a casualty or simply a trapped bird. Once able to catch it, I walked the bird south toward Edmond Low Library and found it a dense and secluded place to perch and rest where it might feel protected – or at least better protected than out in the open of the portico.  I was pleased to see that the bird grasped a branch strongly and seemed to perch well.  This one had me on the fence a bit, but I ultimately logged it as trapped. Though stunned, it seemed otherwise healthy with fat score = 2.

26 September 2016 – Lincoln’s Sparrow

We finally had a decent cold front push through with the first nip of autumn in the air but, unfortunately, it also brought us the first Lincoln’s Sparrow casualty of fall.  This was an AHY-U, bulging with fat (scored it a 3).  This one is also the first window casualty in front of a treated window.  I can’t tell if the bird flew into an untreated pane above the treated area or if it hit one of the treated panes.  That’s a design flaw of my study, stemming from the logistical challenge of treating such large expanses of glass.

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Lots of birds were moving through campus today.  I found a pair of Brown Thrashers and this Grasshopper Sparrow flitting around the plantings in the southwestern alcove.

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23 October 2013 – Lincoln’s Sparrow (plus bonus Lincoln’s Sparrow)

Lincoln’s Sparrow has been taking it on the chin lately.  This morning I found one of those puzzles of a bird on its southbound migration (fat = 3) heading north:

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I also found a second Lincoln’s Sparrow at the Food and Agricultural Products Center.

1 October 2012 – no casualties, but some bonus birds nearby

There looked to be a House Wren and two Lincoln’s Sparrows hanging around this morning, but I still can’t consider these birds “trapped” if I can’t get close enough to them to effectively herd them away from the building.

I did find a window-killed Lincoln’s Sparrow at a nearby building yesterday, and it seems to have hit the same window that an unfortunate Common Yellowthroat did a few days ago.

This building is the Food and Agricultural Products Center, located just west and across a parking lot from the Noble Research Center.  This is a weird little corner of the building that every year claims several birds, even though it seems very protected.

Northeastern corner of the Food and Agricultural Products Center. The two victims are visible, with my backpack for scale.

28 September 2012: Lincoln’s Sparrow and Whip-poor-will

This morning, this Lincoln’s Sparrow was the unfortunate first victim of the season on the south side of the building.  This individual was beautiful and fresh, with a fat score  = 3.


Today I also found the scavenged remnants (two tail feathers and a few contour feathers) of the 42nd species I’ve been able to confirm as a casualty at the Noble Research Center since 2009: an Eastern Whip-poor-will.

The two rectrices (tail feathers) at left are diagnostic for an adult (AHY) female Whip-poor-will, a first for the study.

Whip-poor-will is a surprising find for the study – to say the least.  In my time in Oklahoma, I’ve yet to hear a Whip-poor-will.  We seem to be all Chuck-wills-widows around here, and Whips seem to be confined to our easternmost counties.  Here’s an eBird map for Whip reports in the month of September for the past 10 years:

 

21 September 2012 – Clay-colored Sparrow and Black-and-white Warbler

The north entrance and northwest alcoves were deadly again last night.  This time the victims were an ASY female Black-and-white Warbler and an AHY Clay-colored Sparrow.  The Dickcissel and Lincoln’s Sparrow carcasses have been removed.

Clay-colored Sparrow at the northwest alcove

Female Black-and-white Warbler at the north entrance.

Casualties piling up at the Noble Research Center

 

 

19 September 2012 – Lincoln’s Sparrow

Though we’ll top out around 87 F today, autumn must be in the air because today I found my first Lincoln’s Sparrow on the ground.  I left the bird in place, just opposite the Dickcissel.

It looked like two House Wrens, a Grasshopper Sparrow, and at least one other passerine were still hanging around the north entrance to the NRC, but I haven’t added these birds to the “trapped” list just yet (other than the one House Wren, that is).

5 November 2011 – Lincoln’s Sparrow scavenged, and replaced

It hasn’t been a good few weeks for Lincoln’s Sparrows around the Noble Research Center lately.  The bird I found yesterday has been scavenged. So it lasted one day.  It was replaced by this new one I found this morning:

4 November 2011 – Grasshopper Sparrow and no net loss of Lincoln’s Sparrow

I found this AHY Grasshopper Sparrow (fat = 3) in one of the west alcoves this morning, after a night when temperatures in Stillwater dipped to 23 F.

As for the cryptic headline about Lincoln’s Sparrow, the individual I left in place on Oct. 27th was scavenged overnight.  Here’s what’s left:

So that bird lasted in situ for 9 days.

The “no net loss” comes from discovery of a new Lincoln’s this morning, and this is one I’ve missed for a few days.  How could I miss a dead bird in place for several days when I’m searching an area of lawn and sidewalk?  In this case, it comes down to the where the bird ended up.  It’s so close to the edge of the sidewalk that it’s only visible if approached from the south or east.  My normal walking route approaches this spot from the north, but occasionally I switch things around for exactly this reason.  Even something as simple as the direction of the route you take around a building can affect your ability to detect a bird carcass there.  (I’ll now leave this bird in place and see how long it lasts.)

27 October 2011 – four sparrows hit the end of the road

The four sparrows I found this morning might mark the deadliest evening I’ve seen in three years of searches at the Noble Research Center.  I found birds on three sides of the building after a cool and rainy night.  The first was a bedraggled Lincoln’s Sparrow (fat = 2) that I left in place for a check on scavenging rate.  Elsewhere, I collected these three Grasshopper Sparrows.  The two dry ones on the left were a few feet from each other on the south side of the building, the wet one on the right was in one of the west alcoves.

I aged all three as AHY and all were fat: 3, 3, and 2 from left to right.  Interesting to see the variability in dimensions of these birds, however.  Numbered 1, 2, and 3 from left to right, check it out:

1: 20.5 g, bill 10.6, wing 60, tarsus 23.2

2: 16.5 g, bill 9.2, wing 58, tarsus 21.5

3: 18.0 g, bill 10.4, wing 64, tarsus 22.8

26 October 2011 – two sparrows

A fairly strong cold front moved through last night, with some gusty storms.  This morning I found a Song Sparrow (below, left: AHY, fat = 2) on the north side and a Lincoln’s Sparrow (HY, fat = 3) on the south side of the NRC.

13 October 2011 – Clay-colored Sparrow and trapped Lincoln’s Sparrows

It was a busy morning at the NRC after a crisp and clear, moonlit night that must have supported a big local flight.

I first checked on the Grasshopper Sparrow carcass – still there.

Next, I noticed a trapped Lincoln’s Sparrow on the north side of the building. This bird was flying well and should be OK.  In the west alcoves, however, were three more Lincoln’s Sparrows.  One was moving fine, one I was able to herd away from the building, and one was stunned enough that I was able to catch it.  I carried that bird around for awhile and it seemed quite perky in the hand.  I released it in the dense cover on the south side of Ag Hall, and the bird flew strongly away from me.  I will assume that it will be OK, so the tally will be 4 trapped Lincoln’s Sparrows with no casualties among them.

A fifth sparrow was not so lucky: this Clay-colored Sparrow I found on the east side of the NRC.

2 October 2011 – Nashville Warbler and Lincoln’s Sparrow

Today I found a Nashville Warbler (AHY-U, fat = 2) and a Lincoln’s Sparrow (AHY-U, fat = 1) in one of the west alcoves.  I left the warbler in situ as its beak had broken off and it wouldn’t be as useful as a specimen.  Interestingly, the bird was molting, with several pinfeathers along the sides of its breast.  I collected three outer rects and left the rest of the bird there to see how long it lasts before being scavenged.  The sparrow was in great shape, for a dead bird.

 

Six-month summary: July–December 2010

Here is just a quick summary of casualties at the Noble Research Center from July through December 2010:


Very fat Mourning Warbler that never made it to the wintering grounds.

I detected 25 individuals of at least 16 species among the casualties. The complete list:

grasshopper sparrow – 4
ruby-throated hummingbird – 2
mourning warbler – 2
song sparrow – 2
Lincoln’s sparrow – 2
unidentified passerine (1 warbler, 1 sparrow) – 2
black-and-white warbler – 1
Carolina wren – 1
mourning dove (juv) – 1
least flycatcher – 1
common yellowthroat – 1
black-throated green warbler – 1
brown thrasher – 1
house wren – 1
red-breasted nuthatch – 1
white-throated sparrow – 1
field sparrow – 1

Because I was able to get to the NRC earlier each day during autumn than practical in 2009, I encountered more individuals that were stunned and “trapped” by the building for some time period without obvious mortal injury. Most of these birds are presumed to have eventually moved on, but it is quite likely that the house wren and one of the Lincoln’s sparrows on the “stunned” list were unsuccessful in their respective bids to escape from the confusion of the NRC, and are listed above. The bat represents the first mammalian “capture” by the NRC:

Lincoln’s sparrow – 5 (4 in one flock)
house wren – 1
common yellowthroat – 1
Nashville warbler – 1
grasshopper sparrow – 1
dark-eyed junco – 1


It’s dark when migrants like this Lincoln’s sparrow drop out of the sky and try to find a good spot in which to rest for the day. I’m beginning to think that most collisions are occurring in that last hour before sunrise.

13 October 2010 – flock of Lincoln’s Sparrows

As the season progresses and I’m on a new schedule that gets me to work by 7:30 am, I’m ending up checking the NRC ever closer to dawn. This morning I heard several flight calls while out in the dark around 6:30; when I reached the NRC by about 7:20 (twilight) I flushed several small birds from a juniper border (~ 1m high) around the lawn surrounding the building. At least one was a warbler; the others appeared to be Lincoln’s Sparrows and Chipping or Clay-colored Sparrows.

When I got to the north side of the building, there were 4-6 Lincoln’s Sparrows in the bushes right at the glass. This event afforded me the rare opportunity to watch these birds right as they were looking for a place to settle in for the day and just as they were becoming trapped by the funneling effect of the building’s shape with its several recessed alcoves. As I herded individuals away from the glass, some bumped into other panes (at low speed) and simply flew away (just a foot or so above the ground) directly into the next adjacent alcove. So while there were no casualties today, there were probably 4 Lincoln’s Sparrows that became trapped by the NRC. Here’s one of them:

10 October 2010 – scavenged sparrow and a mammalian surprise

I found another one of those instantly scavenged individuals yesterday, this one identifiable as a Lincoln’s Sparrow from the lone undertail covert and distal end of one wing I found:

The real excitement, however, was furnished by this little guy:

Did you see him?

This was a very much alive (though a bit waterlogged following an afternoon storm) big brown bat. I couldn’t tell if the bat was stunned from striking a window or simply ended up at this spot and was acting unobtrusive as best it could. I didn’t think it would fare well out in the open either way, so I moved the little forest sprite to a nice, protected tree well away from the NRC.

A few moments later, the bat was gone!

No worries – it crawled deep into a crevice in the main crotch of the tree.

7 October 2010 – Lincoln’s Sparrow

So over the past several days I’ve found a Lincoln’s Sparrow and a House Wren hanging around the NRC, apparently unable to figure out a way to fly away from the building. Over the past two days I’ve found a dead House Wren and a dead Lincoln’s Sparrow at that building.

AHY-U, fat = 0

1 October 2010 – no casualties, but . . .

Again I found a confused Lincoln’s Sparrow trapped on the east side of the building. It made me wonder if it actually hurts these birds to fly the “wrong” way when they’re on migration. It’d be so easy for this bird to escape by simply flying about 100 m north and proceeding around the NRC. But when I flush it, it flies E-W and S – it won’t go north, to freedom.

A Year in the Death – Aug. 2009–Aug. 2010

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:

Effort.
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.

Data.
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.

I encountered more casualties during spring and fall migration periods than in winter or summer (though effort may have played a role in this result):

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.)

Non-lethal collisions.
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

Scavenging rate.
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.


Scavenged Swainson’s Thrush.

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.

Total data.
The following table lists all the species found as window collision casualties at the Noble Research Center, 8/20 2009–8/20 2010:

species number
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

O’Connell2001

26 October 2009 – two sparrows

Found another Lincoln’s Sparrow today, and a Song Sparrow that was still alive but not looking good (blood from bill). I moved the Song to a more protected location – he perked up when I grabbed him, so he might have a chance, but I’m including him as a casualty.