Saturday, January 21, 2012

Crossbills and Butterbutts

Much to the neglect of my neurobiology homework, I opted to chase a large flock of White-winged Crossbills reported a few days ago from Park Lyndon North in Washtenaw County.  Reports of large crossbill flocks were abundant from the Upper Peninsula early this winter, giving me hope that a few might wander into southern Michigan this year.

Yellow-rumped Warbler

Immediately after stepping out of my car, I saw a sizeable flock of birds foraging low in a shrubby edge to a pretty steep hill covered in deciduous trees.  To my delight, the majority of the birds turned out to be Yellow-rumped Warblers!  Dan Sparks-Jackson has reported a few hanging out in this area for a few weeks now, so I wasn't entirely surprised to see and hear them 'cheking' away.


Berry wars!

These birds seemed to be doing a lot of foraging on a patch of poison ivy berries, but I also noticed a blue-colored berry of some sort in the bill of the bird in the first picture (also pictured just above).  If you have any idea what it might be, I'd love to hear from you!  The flock of at least 9 birds was associating with a few Eastern Bluebirds, a Downy Woodpecker, and a White-breasted Nuthatch and spent the majority of their time right on the edge, which was receiving a lot of sun (which felt great to me as well!).  As of late, I've been collecting data on overwintering Yellow-rumped Warblers in central and southern Michigan as a part of a little personal project aimed at documenting habitat selection by overwintering butterbutts.  So far, it seems that areas around small, wooded streams with shrubs and poison ivy berries are the preferred environments of this hardy warbler.  This particular spot is a bit of an oddity as, for all I could tell, there is no nearby water.

And to think, come May, no one will care

After a bit of a walk that yielded little else in the way of birds, I found myself in the tamarack swamp that the crossbills had been spotted in.  While the cone crop was very good here, nothing was seen or heard for around an hour.  Even when the silence was eventually broken, it was only done so by a single female/juvenile crossbill that flew briefly over the swamp.  Eventually this bird returned for a few minutes, affording long looks at little more than a silhouette feeding on tamarack seeds.

 ...

After a couple hours of patiently waiting with little more than distant call notes and chatter, many of the 10 or so birders that had gathered in the area left rather disappointed.  On their way out, however, a pair of birders spotted 5 or so crossbills and called the rest of us over.

...better...

As we marveled at the chromatic brilliance of the adult male pictured above, it soon became apparent that there were many more birds.

!

Birds continued to congegrate in the same tree, seemingly coming out of hiding from every possible direction.  The highest count anybody managed was somewhere around 40 individuals.  Unfortunately, malfunctioning recording equipment (i.e. me forgetting to replace the batteries) prevented me from recording the incredible diversity of vocalizations produced by this flock, not to mention the surprisingly audible tune of tamaracks getting pwned in an evolutionary arms race.  Disappointing as that may be, my incompetence did allow me to focus all of my attention on photographing crossbills, which is never a bad way to end an afternoon.












Interestingly, I noticed that the birds would often forage in trees that had far less cones than others mere feet away, but that the preferred trees were less cluttered than the others both in terms of branches and vegetation structure and proximity to other trees.  A fellow birder celebrating his life White-winged Crossbills and I speculated that these 'more open' trees might be preferred for detecting/evading aerial predators.

The northern skies were good to me today, even if they did not deliver the spectacle of charged solar particles that I was hoping to marvel at tonight.

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