Saturday, 8 November 2014

Meadowlark Calls

With the realization that calls might need to be recorded to figure out what the Newfoundland Meadowlark is, I thought I should compile all the different types of calls into one spot.


Both meadowlark species have a call, a rattle call, and a flight call. Have fun!

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A couple resources here:
http://pjdeye.blogspot.ca/2009/02/blackbird-calls-ii-orioles-and.html
http://pjdeye.blogspot.ca/2010/12/blackbird-flight-calls-ii-orioles-and.html
http://www.xeno-canto.org


The call:
Described as (Sibley Guide):

"sharp, electric dziit or jerZIK" for EAME;

"low, bell-like pluk; blackbird-like but more musical" for WEME.





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The rattle call:
Described as:
"hard, mechanical rattle ztttttttt" for EAME
"slow, dull rattle vidididididi" for WEME



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The flight call:
Described as:
"thin, rising veeet or rrink" for EAME
"slightly lower than Eastern" for WEME


Friday, 7 November 2014

A Meadowlark Appears

About a month ago I came across an abandoned field somewhat close to my house that I had previously been unaware of - my immediate impression was that it might be a good spot for sparrows and meadowlarks. I've since checked it 3-4 times, purposefully criss-crossing the field in hopes I'd flush something up. During my first visit there were sparrows everywhere - but none of them were unexpected species. The next couple visits turned up nothing. This morning I happened to be passing by that same field and had meadowlarks on my mind. Wishful thinking of course. But today was one of those days where a dream came true and within a minute of walking out into the field I saw the distinctive shape of a meadowlark flutter towards the ground with its prominent white outer tail feathers.

Even with that 2-second look I was confident enough to send out the text messages. Less than a minute later I had a few "on my way" replies. I flushed the bird once more (it wasn't visible on the ground) and confirmed my previous 2-second view that it was a meadowlark. Lisa was the first person to arrive, she eventually got great photos of the bird in flight - one would think the photos would make the identification straightforward, but it isn't so easy. Even Pyle acknowledges "that this is one of the most difficult in-hand species identification problems" - this is coming from a guy who has probably held hundreds of them in his hand. Today we're stuck with one bird and distant photos.


Without having heard the bird vocalize I had to go to school... photos started streaming into my inbox a couple hours later and things were looking very interesting. Thankfully Lisa de Leon, Ken Knowles, and John Williams all got excellent photos and have been kind enough to let me post them here to help sort out the ID. See Lisa's post for more photos.

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Jared Clarke and I have been trying to sort out the ID since this morning. We haven't made any conclusive identifications yet - but, I hate to say it, I don't think this bird is identifiable without hearing it - the few useful plumage characteristics that are described in the literature fail to separate this bird into EAME or WEME - instead the features are intermediate between the two species. In the mean time, here's a compilation of the most useful photos and information that we have gathered.


To start, the most reliable way to separate these two species is by their voice. At this time of year the birds will only call - thankfully the calls are quite distinctive. However,  I'm not sure if anyone familiar with the different calls actually heard the bird today.


The Eastern Meadowlark call is described more as a "dziit" versus a "pluk" from the Western Meadowlark. To me the EAME call is more like a fart!





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Included here are 7 photos of todays bird (thanks again to Lisa, Ken, and John!)

EDIT: In my original post I made a noob mistake by reversing the numbering of the rectrices. It didn't really change what the outcome of the discussion was, but probably confused some people! It should all be fixed now...


One of the main plumage characteristics described to separate WEME from EAME in the fall is the extent of white on the rectrices (tail feathers). Meadowlarks have 12 rectrices - they are numbered from inside to outside:


The next photo shows that R6, R5, and about half of R4 are white, while there is a small white area on R3.



Here is a scan of Pyle's diagram of meadowlark tail patterns. EAMEs range from figures A - C, WEMEs range from B - D. So there is obviously quite a bit of overlap. However, the only really expected sub-species of EAME in our area (S. m. magna) has the least amount of white in the rectrices compared to the other sub-species - figures B-C are the only relevant ones for the expected sub-species of EAME.

 Our bird falls somewhere between C and D - much closer to D in my opinion - because it has a small white area along the shaft of R3, and the outer edge of R4 is dark.




This photos shows the dark outer edge to R4.


Another useful resource for studying the Newfoundland Meadowlark has been this website. A feature they point out is the extent of dark along the centre portions of the middle rectrices. EAMEs have more extensive dark areas that are all connected along the centre, while WEMEs have lighter areas that separate the individual dark bars.

This feature is very hard to pick out from todays photos - and considering the wide variation I would say it's best not to make a judgement on what we're seeing. The next two photos come closest to revealing the central rectrix pattern.





A study by Lanyon et. al in 1996 involved hybridizing Western with Eastern Meadowlarks. The resulting rectrices are shown below with Eastern at the top, Western at the bottom, and the hybrid of the two species in the middle.

Our bird fits best with the hybrid combination... the dreaded hybrid...
This is not meant to say that the Newfoundland bird is a hybrid. But certainly indicates that it isn's a "slam-dunk" Western Meadowlark.

This study can be found here.

An important quote from this study:
"Extensive overlap in all mensural characters and in the amount of white in the rectrices precludes the use of these characters for identifying all but the "extreme" specimens."




Other plumage characteristics often talked about are the malar and flank patterns.

Malar pattern is pretty much useless in the Autumn. For what its worth, the malar area on todays bird is buffy. Not white, not yellow.


Flank streaking on Easterns averages heavier and more merged - again, an unreliable feature from what I've been reading.



From all this, I would say that this bird isn't 100% identifiable based on plumage characteristics. Vocalizations are a hope. That won't happen tomorrow though with 100+ km/h winds!!

FWIW, several out of the province birders with a lot more experience with meadowlarks have unanimously said they "think" that it's a Western Meadowlark.




Thursday, 6 November 2014

White-rumped Sandpipers Arranged By Plumage

Juvenile White-rumped Sandpipers start arriving in good numbers in late September in Newfoundland with quite a few still here now (early November), and will probably continue to be seen into December.

What's interesting about these juvenile birds is their huge variation in progression of their moult into 1st winter plumage. When the birds hatch they immediately start growing their juvenile plumage which generally consists of bright reddish/orange upper part and upper wing feathers that are fringed with white. During their southward migration they begin moulting into their first winter plumage. Ultimately, this moult is "complete" - meaning that all feathers are replaced (note that most sandpipers have an "incomplete" moult into first winter plumage, WRSAs are an exception). Although all feathers are replaced eventually, only the body feathers, scapulars, and possible wing coverts are replaced during migration - the flight feathers (primaries, secondaries) are replaced on the wintering grounds.

The replacement of mantle feathers, and scapulars is visible in the field and although it doesn't serve much help in identifying them, it can provide an appreciation of bird moult and is just plain interesting!

This juvenile White-rumped Sandpiper has replaced about 10 mantle feathers, and 2 scapular feathers on both sides. The arrows point to the new feathers which are noticeably duller than the old juvenile feathers. These new feathers are part of the 1st winter plumage. So technically this bird is transitioning from juvenile to 1st winter plumage.

These are the feathers to look for when studying/observing the moult of White-rumped Sandpipers at their stop over sites.

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The following 11 photos are of White-rumped Sandpipers taken at various locations and times this Autumn. I've arranged them, as best I could, from full juvenile plumage to first winter plumage.


1: this bird has replaced no scapular feathers, but has replaced a limited # of mantle feathers.

2: one scapular feather and a number of mantle feathers replaced

3: similar to above

4: two scapular feathers and about 10 mantle feathers replaced

5: at least 4 scapulars and what seems like a majority of mantle feathers replaced


6: ~7 scapulars and 80%+ mantle feathers replaced


7: ~eight scapular feathers and 80%+ mantle feathers replaced

8: similar to above


9: similar to above - a whole row of scapulars appears to be replaced here

10: similar to above, but the arrow points to one of the scapular feathers that borders the mantle feathers. So far in the sequence of photos, this is the first bird to have replaced a feather along that tract/row.

11: the most advanced plumage I have photographed this season - many scapulars replaced including those that border the mantle feathers; no wing coverts have been replaced - they continue to have the white-fringing associated with the juvenile plumage of most shorebirds.



Once these birds reach their full first winter plumage they'll have replaced all their feathers. 
Come the spring, they will begin another moult which generally involves replacing only body feathers, the scapulars, and some wing coverts.