Friday, March 9, 2012

A Quest for the Golden Swamp Warbler

Ever since I really got into birding (almost four years ago now) and started exploring the woods around my house through the eyes of a birder, one question has been burning in my mind that remains unresolved to this day: where are the prothonotaries?

Unlike many similar questions I've had concerning the absence of species despite apparently suitable habitat, which are often settled after either finding the species or discovering some critical piece of missing microhabitat, the more I learn about Prothonotary Warbler habitat, the more perplexed I am at their truancy from this area.


This is a map of the area in question, with apparently suitable habitat for prothonotaries highlighted in yellow, both bordered by bodies of water (Grand River to the north and Williams and Browns Lake to the south).  Specifically, these areas are what I would generally call flooded hardwoods, dominated by Red Maples, oak spp., elm spp., and birch spp. (my guess is River Birch, but I have little experience in tree identification).  As you might guess from the nature of this post, this is exactly what prothonotaries prefer to nest in (at least when they're this far north).  Here a a few shots of the habitat from yesterday:





...including a couple close-ups of key trees...
Beech

Birch spp.

I think this is a Red Maple...


A bit of searching around on the web has revealed that the following habitat features are important in habitat selection for Prothonotaries:

1) Prefer to nest over large bodies of standing/slow-moving water -- this area borders a slow-moving portion of the Grand River, two lakes, and usually remains flooded well into June/early July.

2) Low elevation and flat terrain are preferred -- low elevation is definitely 'achieved' here and the flooded woods themselves are flat, though the deciduous forest between them is fairly hilly.


3) Canopy height of 12-40 m with 50-75% cover -- yes on both accounts.  There's also a fair bit of diversity in both tree age and canopy cover, both apparently due to fallen trees, which is an indicator of a healthy, mature forest.


4) Forest ≥100 ha -- a quick and dirty estimate using Google Earth puts the northern portion at 13 ha and the southern portion at about 17 ha.  This might be the most obvious factor preventing prothonotary presence, though I'm not sure if this is limited to flooded areas where the birds would directly nest or the forest as a whole.  At any rate, the entire area only comes to about 33 ha.  This does not include adjacent areas that are, for the most part, fragmented only minimally by a few roads and houses.

5) Low exposure to sun -- plenty of this.

Despite the potentially limiting factor of acreage, I plan on installing a few nest boxes in the weeks to come in hopes of luring some warblers into the area this spring.  As many as eight warblers have been reported singing from the Grand River just north of town (in the Berry Rd. area), so I'm somewhat confident that prothonotaries might at least travel through this area (indeed, I got my life Prothonotary during fall migration of 2008 at Dahlem).

A few additional shots from yesterday's trek:

Filamentous green algae(?)

Bark beetle work...

...and a close-up


I'm not sure what's going on in this last photo, but this really stood out against the rest of the dark leaf litter below the water.  Whatever this is, it appeared to be pretty superficial, being restricted to a small layer on top of the leaves.


This is an attempt at cellestial photography that I made at something like 1:00 am yesterday while waiting in vain on the aurora borealis.  I think my telephoto lens has interesting potential for this type of stuff, but I'll definitely need to get my hands on a tripod -- this photo only managed to turn out semi-decent due to the strategic use of my roof as a steady base.
And finally, even though the majority of this post is dedicated to birds, it wouldn't be right to publish this without a single bird photo.

Eastern Phoebe

Don Henise found this yesterday, which is pretty early for this species.  Spring is here!



Wednesday, March 7, 2012

Catching Up

The past few weeks have been absolutely insane for me, leaving little time for posting.  In fact, yesterday was the first day that I'd gotten out and actually done some extensive birding in something like two weeks, when Don and Robyn Henise found a Northern Saw-whet Owl at the MacCready Reserve in southern Jackson County.

Northern Saw-whet Owl

This bird was roughly 20 feet up in a spruce tree and was quite a ways off the trail (hence the iPhone digiscoping).  I always assumed my life saw-whet would be closer to the ground, as I always hear of people finding them in dense conifers or deciduous scrub, usually no higher than eight feet off the ground.  At any rate, I was ecstatic to finally lay eyes on one of the hardest owls to find in Michigan.

Some other highlights from that day:

White-winged Crossbill

Red-tailed Hawk

Two of seven Sandhill Cranes

Spring has really made an appearance over the past week or so, with Red-winged Blackbirds, Common Grackles, American Woodcocks, and a slew of waterfowl being reported in southern Michigan.  Even winter residents are showing increased activity as of late, especially noticeable in the songs of common yard birds such as Northern Cardinals, American Robins, House Finches, and Eastern Bluebirds.  A brief hike at Dahlem something like a week ago (I have no sense of time elapsed over the past month) yielded a large group of bubbly bluebirds around the ephemeral pond, allowing for great photo opportunities.





The group seemed to be foraging on insects of some kind along the edges of the pond, which had pockets of open water.  One female even seemed to be scouting out a prospective nesting cavity in dead, truncated stump at the edge of the pond.  A heavily cropped photograph of the shot above (see below) almost makes me think that this bird is feeding on a stonefly larva, but all sources I've looked at indicate that stoneflies prefer swift lotic systems with high levels of dissolved oxygen which does not describe this pond.  If you can identify this bugger, I'd love to hear from you!

Identify (the one without the vertebrae, that is)!

Another welcomed sign of spring was the appearance of flowers on campus this past weekend!  I thought for sure that, like every year, snowdrops would be my first flowers of the spring, but instead I stumbled upon these at Michigan State's Beal Garden (I'm actually worse at identifying plants, so, as always, help is appreciated!).


A beautiful sight on a dreary, windy, snowy March day

I spent a day in Jackson on Tuesday, offering a brief but much-needed break from life in East Lansing.  I originally intended to search for White-winged Crossbills in a small spruce and hemlock stand in the Williams Lake area.  Given that it was much too windy for any passerienes to be foraging in the tops of trees, I headed into the stand to search for owls.  In my mind, this place had seemed like the perfect spot for a winter saw-whet or long-eared, given that it lies adjacent to a small field, the preferred hunting habitat for both of these species.  Within minutes, a smattering of pellets of whitewash made it blatantly aware that someone had spent a lot of time here this winter.  The whitewash at the base of one tree was particularly concentrated, so I looked up to find a small, white rump staring right back at me.  Even from this (potentially catastrophic) view, I knew what I had.


Possibly my favorite, personal find to date

It seems like I've spent at least the past two winters obsessed with trying to find this species.  Countless hours obsessing in vain over the potential of every suitable (and even those of not-so-suitable qualities) cedar stand near water or grove of dense hemlocks to hold these small and incredibly elusive owls of the boreal forests.  I'd even recently come to the point that I'd given up much hope of deliberately pursuing and finding a saw-whet and figured that I'd eventually find one when I least expected it.  Don and Robyn's find certainly struck that chord, but literally stumbling into this bird was an incredible surprise.

After showing the saw-whet to a few friends and picking up two Barred Owls calling in the nearby woods at 4:00 pm, I ended the day with a large, mixed group of icterids calling in the cottonwoods above the cattail marsh behind my house, brilliantly illuminated by the refracted light of a golden evening sun.

How many icterid species do you see?

A brief afternoon jaunt just outside of East Lansing with fellow over-worked and under-birded spartan, D.J. McNeil yielded MANY American Robins Red-winged Blackbirds, Common Grackles and little else, though you won't hear me complaining quite yet...


conk-la-ree!

About a half-hour after sunset, we came across a male robin singing very softly from a low perch amongst a thicket of buckthorn on a stream bank.  Intriguied by the behavior, we sat and observed the fellow for a good 10 minutes and a couple of things caught our attention.  First, it seemed that this bird was deliberately keeping his tail spread during his singing, even going so far as to flick and waggle his tail.  During this, we also noticed that the white tail corners, which birders probably don't pay much mind to, really stood out in the dim light, almost appearing luminescent.  Instantly, I began thinking about how some owls (e.g. Great-horned and Great Gray) have a white throat, which I've often heard (but can't confirm) plays a role as a mating signal.  Interestingly, Tyler (1949) notes that a very similar behavior to the one we observed constitutes the courtship display of American Robins, the main difference being that no female was present today, only another male who took exception to the display.  Given this information, I'm really curious about the function of these tail corners, especially considering that they are much reduced in western birds...

Oh, and we heard a Western Chorus Frog!

 Tyler, W. M. 1949. Eastern Robin. Pages 14-45 in Life histories of North American thrushes, kinglets, and their allies. (Bent, A. C., Ed.) U.S. Natl. Mus. Bull. no. 196.


Sunday, February 5, 2012

More Crossbills

There's nothing quite like finding birds at a spot that you've been expecting them for months.  Such has been the case for me, White-winged Crossbills, and Ella Sharp Park.  Every time I've been home since late December I've made it a point to check out the spruce trees around the rotunda (which are loaded with cones) for these nomadic finches.  But, alas, my efforts have been fruitless, until today when I found a small flock of five birds.  Recording conditions were difficult, as the park was well-visited by the noisiest hobbyists Jackson has to offer, including RC airplane and car enthusiasts who showed little concern for my auditory exploits.  And, naturally, I didn't have my camera on hand, as I seriously doubted that I'd find anything worth hauling that thing and my recorder around for.  Figures.

I really shouldn't be complaining, though.  At the beginning of the season, I didn't have a shred of hope for finding any northern finches in southern Michigan this winter, as Ron Pittaway's Winter Finch Forecast seemed to indicate that cone crops were sufficient in southern Canada to keep crossbills and redpolls from moving south.  Meanwhile, White-winged Crossbills have made a significant push south over the past month or so, even into Ohio, and redpolls have done the same over the past couple of weeks.  What's perhaps most bizarre is the number of Hoary Redpolls in southern Michigan and Ohio at present.

Sunday, January 29, 2012

Red-breasted Satellites

While hiking at the MacCready Reserve in southern Jackson County a few weeks ago, I heard what I was pretty sure was a White-winged Crossbill fly over me twice, but subsequent attempts to find the bird (or the flock that it was hanging out with) were unsuccessful.  This Friday, Don and Robyn Henise found a small flock of crossbills at MacCready, so this morning I went out to try and make up for my missed opportunity to record crossbills last weekend in Washtenaw County.

To make a long and disappointing story short, I found no crossbills, though Craig Robson and Heidi Doman did have a single bird fly over just prior to my arrival.  We also found evidence of recent crossbill activity, such as bits of tamarack cones on top of the snow (indicating very recent activity, given the snow accumulation today) and mangled Norway Spruce cones.

After parting ways with Heidi and Craig, I stirred up a mixed flock of birds in a transitional area between a small spruce stand and the red pines that dominate the majority of the reserve.  I actually got the attention of the birds by playing a White-winged Crossbill recording, which prompted a single Red-breasted Nuthatch to call.



Instantly, the calling of the nuthatch prompted a mob of chickadees, a few Blue Jays, a couple of White-breasted Nuthatches, and a Downy Woodpecker to swoop down and begin mobbing me.  I had hoped to record the entire succession of the encounter to illustrate some of the dynamics of mixed species flocks.  Unfortunately, in addition to having a dead camera battery, my recorder was having problems with the memory card, allowing me to make only brief bits of recordings as the scene unfolded.  I would later find a single Ruby-crowned Kinglet in this flock, which really got me down about my camera being MIA, given the rarity of this species this far north during the winter.

During the winter in temperate North America, chickadees, nuthatches, kinglets, woodpeckers and a few other species (e.g. Brown Creepers) aggregate in small flocks that travel and forage together.  This is thought to be a strategy that is selected for based on the benefits individual flock members can accrue, such as increased foraging efficiency, reduced risk of predation, and reduced vigilance that is required from each individual to detect predators (Sullivan 1984, Dolby and Grubb Jr. 1998).

What I find particularly interesting is the fact that the two groups of birds that are almost always found in these flocks (Parids and Sittids) have distinct functional roles within the flock during a predatory encounter -- roles that reflect the differences in the ecology of the two groups.  Nuthatches are primarily bark-foragers that are usually found high in trees, while chickadees and titmice tend to forage lower in the canopy and can be found foraging in shrubs, on tree branches, the ground, and even the bark of trees.  These differences are maintained in mixed flocks and have given rise to the terms satellite and nuclear species, respectively, to describe the spatial relations of these two groups.  This concept is not restricted to temperate North America, and species in a variety of ecosystems at (almost) all latitudes engage in similar relationships.

Depending on where a potential predator is approaching a mixed flock from, either group might be more likely to alert other members of the flock with an alarm call.  I've often noticed that when a hawk flies over or I approach a flock of birds from a distance in an open area, nuthatches and woodpeckers are usually the ones to expose my whereabouts.  Conversely, many a time I've watched Snapper wander into a patch of thick bushes, rousing the suspicions of chickadees and titmice.  This fits well with the available literature, which indicates that nuclear species are more likely to detect terrestrial predators in low-visibility situations, whereas satellite species are likely to detect aerial predators approaching the flock from a distance.

I actually did a little project on mixed flocks for an independent study last year.  Specifically, I was interested in finding out if there are any key parameters of alarm calls that birds might hone-in on to assess the level of a threat.  In order to investigate this, I altered different parameters of a White-breasted Nuthatch alarm call that I recorded at Dahlem last winter and conducted playback experiments to birds in the field.  In short, I found that increasing the amount of time between notes (by 4/10 sec.) and increasing the length of the notes themselves (by 5/100 sec.) significantly altered antipredatory responses of birds.  I really have no intentions of publishing any of these data, so below are barplots depicting these results.






The responses on the x-axis are categorical responses, meaning there is no 'order' as you increase or decrease the value.  "0" denotes no apparent antipredatory response, "1" denotes a "freezing" behavior that I usually observed when birds were already in an area with sufficient cover, and "2" denotes a bird immediately fleeing to bushes or other forms of cover.  The trend for the second plot is at least intuitively easy to explain (insert multiple caveats), but I'm still a bit puzzled by the results from the first.  Much to my delight, Ellis (2007) found very similar results when investigating key parameters of alarm calls in White-throated Magpie-Jays, which just might spur me to redesign my study and have another go at publishing the results.

In highly unrelated news, I think it's worth mentioning that the trails at MacCready today were absolutely covered with Snow Fleas (Collembola), which seemed unusual given the relatively cool temperatures and overcast skies this morning.  My only guess is that they might have emerged in large numbers yesterday during the sunny afternoon.  I wonder if the extreme day-to-day variation in weather that we're seeing this winter will have any effect on these hardy little beasts.  Oh, and I also saw quite a few Skunk Cabbage peaking through the snow!


Dolby, A.S., Grubb, jr T.C. 1998. Benefits to Satellite Members in Mixed-Species Foraging Groups: An Experimental Analysis. Animal Behavior. 56(2): 501-509.
 
Ellis, J.M.S. 2007. Which Call Parameters Signal Threat to Conspecifics in White-Throated Magpie-Jay Mobbing Calls? Ethology. 114(2): 154-163.
 
Sullivan, K.A. 1984. Information Exploitation by Downy Woodpeckers in Mixed-Species Flocks. Behaviour. 91(4): 294-311.

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.

Friday, January 13, 2012

Thursday, January 12, 2012

Monday, January 9, 2012

Bananas and Peanut Butter

So the title is a bit of a digression from the usual content of this blog.  Classes started today, meaning I'm a bit short on sleep and enthusiasm.  This is not to say, however, that the sweet and salty title of this post has no relevance to my experiences in nature.  Indeed, as a generally poor manager of time, I often find myself without any time for the trivial pursuit of adequate nutrition (this is especially true when birds are involved).  For this reason, this quick, protein- and carbohydrate-rich snack has fueled the wanderings that are the basis for many of my posts.  Long may it be so (though climate change may have other plans).  If the demise of the bastardized remnants of Hawaii's avifauna, the integrity of the boreal forest, and the salinity of the oceans are not enough to prompt our country to action, then perhaps the loss of PB&J will.

A future relict snack?

On a lighter note (sort of), last week was my final week of winter break, which I usually spend sulking around my house in despair over the days to come, when birds and sunlight are but distant memories of life in the 'before time'.  This year I opted to change this depressing pattern, even if it meant simply getting out of the house in search of birds that I had little chance of finding.

First winter White-throated Sparrow

Inspired by my luck on the Waterloo Christmas Count and Joyce Peterson's find on the Albion Christmas Count, I started out the week searching for Yellow-rumped Warblers in Jackson County.  Based on observations of this species in southern and central Michigan during this winter, it appears that they tend to prefer shrubby, riparian areas with a good supply of berries (particularly poison ivy) and open water.  As luck would have it, such habitat exists mere minutes from my house at Ella Sharp Park.  But despite perfect habitat, I came up empty on butterbutts, though the place was loaded with White-throated Sparrows, which I haven't been able to find anywhere else in the county.

Adult, (putative) tan-striped morph

Within the four or five flocks I encountered, I only saw a couple of white-striped individuals, which seemed odd (though many may have been first year birds that simply haven't molted yet).  White-throated Sparrows exhibit a polymorphism that shows variation in morphometrics, behavior, and, most noticeaby, plumage (specifically in the crown stripes) (Lowther 1961).  Interestingly, this polymorphism has been linked to a very large inversion on the second chromosome that contains about 1,000 genes (Thorneycroft 1966).  Because inversions suppress crossing over (review your meiosis!), this means that the genes within the inversions that 'cause' the different morphs never get mixed together, allowing these sections of the genome to diverge from each other.  What's perhaps even more interesting is that individuals of this species almost always mate with an individual of the opposite morph (Falls & Kopachena 2010), a behavior that may be influenced by this very region of the genome.  Because of this, both morphs are stably maintained within the species and speciation has not occurred, even though this large area of the genome is diverging.  When you consider that this inversion is thought to have occurred around 2.2 million years ago (Thomas et al., 2008), and that it causes many substantial differences in behavior and morphology, it is easy to imagine that, without this quirk of mating behavior (disassortative mating), we might very well have had another Zonotrichia species in North America!  Science is fascinating.


Field Sparrow

After failing to find a butterbutt and having my camera die just before finding a huge flock of American Robins and a Hermit Thrush, I headed home to recharge my spirits and batteries before heading out again, this time with a more realistic goal -- Swamp Sparrows.  I don't know that I'd ever seen a Swamp Sparrow in the winter, though I certainly know they're around in small numbers.  I opted to first look in an area where flooded hardwoods borders cattail marsh near my home, which has been good for sparrows in past years.  Much to my surprise, the Field Sparrow pictured above was the first sparrow I saw.  I assume this is probably a bird from the consistent flock I've posted about previously, given the close proximity between locations.  Interestingly, while the flock is incredibly skittish and difficult to observe in the nearby meadow, this bird was foraging on Reed Canary Grass (I think?) seeds just a few feet from me, paying almost no mind to my phishing efforts directed at his (her?) evolutionary cousins.  This seemed like curiously bold behavior, given that this individual was apparently not in the company of any other birds.

Song Sparrow

No sooner had I forgone my efforts to stir up any other birds when this Song Sparrow and two others started cheking away at me, all while skillfully managing to prevent any decent photographs from happening on their behalf.  Curiously enough, it appeared that the Field Sparrow did react to the calls of the Song Sparrows by taking evasive action into thick shrubs.


Swamp Sparrow

With all sparrows out of sight, I decided to play a few chip notes from a Swamp Sparrow, just to see if one was lurking in the cattails.  Five seconds of the clip hadn't yet passed when this individual sprang up from a patch of grass, chipping away at my iPhone with the exact same calls that I was broadcasting.  I don't know that I'd ever noticed it before, but it appears that Swamp Sparrows have much thinner bills than Song Sparrows.  Interesting.


American Tree Sparrow

Just before I decided to head home, a flock of about ten American Tree Sparrows came dashing into the area and immediately took to foraging all over the place, including on the ice.  A few minutes after the cheerful, metallic chip notes of this flock had been bouncing all over the place, the Song Sparrows and Field Sparrow came out of hiding and joined the group in foraging on top of logs and in grassy patches around tree trunks, though they never strayed far from cover unlike the bold denizens of the Canadian tundra (perhaps a name change is in order).

I originally intended to add details about another unsuccessful warbler quest (this time for Common Yellowthroats), but realized that it would amount to little more than me continuing on about sparrow behavior.  In an attempt to keep you from not ever wanting to look at future posts containing sparrows, I'll just post a few pictures from the day.

One of about ten at Cascades Park

One of about five


How can you not adore chickadees?

...I mean, seriously.

One of many!


Blue Jay


Eastern Bluebird


One of at least six on the Hoffman Trail


Is there a better looking woodpecker in the eastern forest?

 

Falls, J. B. and J. G. Kopachena. 2010. White-throated Sparrow (Zonotrichia albicollis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/128