13 July 2013 – unknown passerine (scavenged)

Of the 138 casualties I have documented on this project there are just four I have not been able to confidently identify, most recently this feather I found Saturday morning:

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The feather appears to be an outer rectrix from a bird that collided with the building and was scavenged in less than 24hrs.  The rachis is dark on the upperside and whitish on the underside. The exterior edge of the vane is olive green without pattern.

The feather is the right size and shape to have come from assorted warblers, vireos, or other species.  I’m okay simply including it as an “unknown”.  There are other single-feather finds that I have been able to identify (e.g., cardinals); this one apparently not.

The feather, together with the ongoing scavenging rate trials a few meters from where it was found, illustrates well the difference between “scavenging” and “removal”.  The Northern Cardinal carcass that I found in June was not scavenged except by beetles, ants, and isopods.  Thus it was never removed from its final resting place.  Weeks later, a single rectrix remains of that bird.  I judged that one day last week I would’ve overlooked that feather in the course of my daily monitoring, so I estimated that it was in evidence for 26 days.  It’s actually still there, however, and I noticed it this morning.  I could keep counting it as “detectable”.  Either way though it illustrates the point:  I could have detected that feather at any point during the 26-day period that it was noticeable and I would have a record of that mortality even though the carcass had technically been scavenged.

With respect to the two buntings and the chickadee from last week, they’re still there even though all have been scavenged in situ:

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From top to bottom:  Carolina Chickadee, Indigo Bunting, and Painted Bunting.  All have been scavenged but none have been removed.  Traces of these birds might last for weeks, increasing my chances of detecting the casualty even if the bird has been scavenged.  What matters is whether or not the carcass has been removed.

9 July 2013 – Painted Bunting and Carolina Chickadee

Casualties continue at the Noble Research Center this week.  Today (actually July 10th) I checked and noticed these birds here since yesterday, so I’m considering them the results of a July 9th survey that I technically did not conduct. Again, we had two birds of different species killed at the same spot on the NRC – the main entrance on the north side.

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The first bird I noticed was the Carolina Chickadee, lying within arms’ reach of the Indigo Bunting I left out the other day:

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About 2 m to the left of the chickadee was this female Painted Bunting:

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Both birds were deteriorated (by beetles, isopods, and ants) to the point at which I wasn’t comfortable examining them for additional aging and body condition criteria.

8 July 2013 – Indigo Bunting and Grasshopper Sparrow

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At first glance, it looked like these two “sparrows” were flying together and hit the same window.  A closer inspection revealed that while they might have ended up in the same spot, they arrived independently.

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Today I found a female Indigo Bunting, apparently AHY. The insects had already gotten to her head – that’s the black “patch” she shows above her eye. This indicates to me that she was actually a casualty from yesterday morning, the 7th.  I moved her to the side and will monitor the progress of her removal.  (The cardinal remains evident to me.)

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A bit closer to the window was this HY Grasshopper Sparrow.  This bird was in excellent condition (fat = 2) in life – indicating that it was migrating – and its carcass was much fresher than that of the Indigo Bunting, indicating that it died more recently.

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This bird I collected and put on ice.  It will be interesting to learn eventually where this bird was born and where it might have been headed so early in the “fall”.

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30 June 2013 – trapped Black-and-White Warbler

I found an apparent SY female Black-and-White Warbler at the northwest corner of the NRC this morning.  The bird had the stunned look of one who’d knocked into a window, but it wasn’t really trapped the way other birds I’ve found have been.  After a few minutes and as I began to approach, it flew strongly to a nearby tree. 

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