Monday, October 7, 2024

Alder and Willow flycatchers, side by side

Back in early June, Shauna and I traveled to rural western New York, to attend the Allegany Nature Pilgrimage. It's quite the event, with hundreds of attendees, scores of field trips and other activities, and lots of speakers. I was there in the latter capacity, speaking about - what else, this year - moths.

The Pilgrimage takes place in a beautiful region with lots of interesting places nearby, so we took the opportunity to tack on a few days and visit some new sites. We saw lots of flora and fauna, managed to eke out some decent imagery, and learned lots about various things. One of the more interesting avian experiences for me was stumbling into a large shrubland that was occupied by both Alder Flycatchers (Empidonax alnorum) and Willow Flycatchers (E. traillii), in about equal numbers.

This vast shrub-dominated meadow is in Iroquois National Wildlife Refuge, about 40 miles northeast of Buffalo, New York. We were slowly cruising by when I heard the song of an Alder Flycatcher. As this is a species that I am very much smitten with, we quickly pulled over and got out to better assess the situation. To my surprise I soon heard a Willow Flycatcher, then another Alder, another Willow, and so on.

This site is near the southern overlap of these species' ranges, and maybe shrublands full of both species isn't that unusual in this zone, but I had never seen it. Where I live, in central Ohio, Willow Flycatcher is the common species, and Alders only occur sparingly in northernmost Ohio, especially in the northeast corner which has the most boreal-ish habitat. But I've spent scads of time in the north country, such as the northern tip of Michigan's Lower Peninsula and the Upper Peninsula, where Alder Flycatcher is very common, and I know it well.

Alder and Willow flycatchers were considered conspecific until 1973, although the differences between the two were noticed long before, perhaps most notably by Roger Tory Peterson. Much of the differentiation is in vocalizations, and habitat. They are well-named birds, as Willows typically occupy areas with some willow (genus Salix). Alders prefer, duh, alders (genus Alnus) and thus are typically found in wetter sites as that's where alder thickets thrive. But good luck identifying a silent bird in migration. If it issues a few distinctive call notes, you might nail it, but otherwise it'll have to go down as "Empidonax sp. Even birds in the hand, with measurements possible, cannot always be separated (ever?).

A male Alder Flycatcher in the Iroquois meadow in the first photo. Its singing perch was a willow. Indeed, we could not find any alders in this damp meadow, just willow of several species.

Here is a nearby male Willow Flycatcher, also teed up in a willow singing perch. We walked around much of this roughly 20-acre site and spent much time listening to and watching the flycatchers. In all, we counted 5-6 singing Alders and 4-5 singing Willows. The birds seemed to have marked out well-established territories, and we saw no interactions between the species. It certainly was a great site to hear both of these look-alikes singing side by side.

A brief, greatly compressed video of one of the singing Alder Flycatchers. Sorry, my learning curve with video processing is not very advanced, but you should be able to hear its distinctive song well. It is a burry ascending Free-beer! or Fe-bee-oh!

I was going to post a singing Willow Flycatcher video that was nearby the Alder above, but now my video "editor" is giving me fits and I can't make it work. I'll try to correct this and post it later. Its song is a quite different sneezy Fitz-bew! With some practice and experience, separating these species by song is normally not difficult. Even the call notes are mostly distinctive, especially the dry whit whit calls of Willows and the more robust pip pip notes of Alders. In fact, the latter species reminds me of a miniature Olive-sided Flycatcher as some of its calls suggest that species, and the territorial males seem more pugnacious and prone to singing from exposed perches.

There apparently is no concrete evidence of hybridization between these very similar species, even though they are extremely similar genetically, much more so than most avian species pairings. Our observations in this mixed meadow, the type of site one might think that hybridization might occur if it indeed does happen, indicated that the two species maintained well-defined territories and did not interact much.

Thursday, October 3, 2024

Brown-headed Nuthatch

 

I've been playing catch-up with photo labeling and archival - note to self: do not fall behind on this. Anyway, one positive is revisiting many cool sites and lots of interesting flora and fauna. This is one of the world's cutest birds, the Brown-headed Nuthatch (Sitta pusilla). The elfin weighs maybe 10-11 grams, and barely exceeds 4 inches in length. For comparison, the White-breasted Nuthatch is 20 g and 5.5 inches - a comparative giant. BHN's are obligatory pine residents and small troupes of them make a gentle cacophony as cute as the birds: it sounds like a dozen kittens are in the limbs, playing with squeak toys. Hickory, North Carolina, January 1, 2024.

Monday, September 30, 2024

American Copper

 

I was pleased to stumble into a small population of American Coppers (Lycaena phlaeas) last Thursday, September 26, in Wayne County (Ohio). This one is nectaring on white heath aster (Symphyotrichum pilosum), of which there was plenty at this locale.

In spite of the name, there is strong evidence that the "American" Copper was in fact introduced to America long ago, perhaps in hay shipments from Europe. In the Old World it is known as the Little Copper or Eurasian Small Copper, and the two "species" are quite similar. Also, the American Copper's host plants (what the caterpillars feed on) are Eurasian species not native here, primarily sheep sorrel (Rumex acetosella) and curly dock (R. crispus). Even if the little butterfly was an unintentional import, it is an attractive and charismatic little butterfly and I'm not aware of any issues that it has caused.

Monday, September 23, 2024

A motherlode of Lincoln's Sparrows

The inaugural Headlands Birding Festival took place last weekend, based at Headlands Dunes State Park. There were a number of breakout speakers on Saturday afternoon, and keynotes Friday and Saturday night. Greg Miller of The Big Year fame was on Saturday, and your narrator spoke about the Great Lakes and their importance on Friday. From what I could tell, there were several hundred attendees, and more people than that wandered through the vendors and exhibitors on Saturday. It was a great time, and I believe this event will only grow. The Lake Erie lakefront in northeastern Ohio is incredibly important for fall migrants, and this makes for great birding as we shall see.

Mentor Marsh was the location of our field trip on Saturday morning, led by Becky Donaldson of the Cleveland Museum of Natural History and me. We met our group of about 25 people at 7:30 am and hiked this elevated dike through the marsh. While the trip was scheduled to end at 9:30, many of us stayed until about 11 am. The birding was magnificent, and the glut of Lincoln's Sparrows was right along this dike. We estimated 15 Lincoln's Sparrows on our trip, but I knew far more were present. Note the pale lime-green zone off the left side of the dike, right before the trees. That's rice cut grass (Leersia oryzoides) forming a large drift. Its fruit was ripe and seemed to attract lots of sparrows.


While field trips are fun, a great way to showcase natural history, and several of our participants saw new "life" birds, large groups are definitely not the effective way to stalk shy, skittish sparrows, especially insofar as photography goes. In fact, I didn't even bring my camera on the field trip. Probably should have but when one is leading, it's rude to become self-absorbed and get into shooting pics and ignoring the group. I don't even want the temptation, although I would have regretted that decision had a Steller's Sea Eagle or something crazy flown by. Anyway, I got permission to come back to this spot the following morning, at the crack of dawn, camera in tow.

This is the view to the north from that dike. The bulk of the 1,000-acre marsh stretches in that direction. I wonder how many Lincoln's Sparrows were up that way. Probably hundreds. I just sampled a tiny portion of the vast wetland - one-half mile in, and the same one-half mile out.

Here's a nice mugshot of a Lincoln's Sparrow (Melospiza lincolnii). It is in the same genus as the Song Sparrow (M. melodia) and Swamp Sparrow (M. georgiana), and is superficially similar to both, especially the Song Sparrow. But once one is familiar with the comparatively dainty and compact Lincoln's Sparrow, with its neatly striped dapper plumage, subtle gray and buff tones, and generally much more animated behavior, they are quite easy to identify.

As soon as I entered the trail, I began seeing Lincoln's Sparrows. At times I could see a dozen at once. In all, I tallied (and eBirded) 75 but am sure that's just a snippet of the true number that was present in the marsh.

Here's a Lincoln's Sparrow in a buttonbush plant (Cephalanthus occidentalis). The sparrows seemed smitten with the fruit - brownish balls on bottom left corner - and this particular shrub often had multiple sparrows simultaneously. I failed to get the money shot of a sparrow with buttonbush seeds in bill, although I saw it happen numerous times.

Many Lincoln's Sparrows were further out in the marsh, like this one teed up in some cattails. They were generally in proximity to the beds of rice cut grass, which is why I suspect they were harvesting its abundant ripe fruit.

In all, I photographed probably 6-8 different individuals. This one popped out very briefly on a branch near the ground. When skulking in dense vegetation, especially on the ground, which is how Lincoln's Sparrows often behave, it can be tough to get even a good enough look to positively identify them.

Here's a front shot showing the fine streaking and subtle buff wash which contrasts with the grayish head. The dapper little sparrows are sometimes said to resemble "well-dressed" Song Sparrows (at least by me).

A Lincoln's Sparrow, on point, showing a classic alert posture with raised crown feathers. This one was part of a group foraging in a small black locust (Robinia pseudoacacia) thicket.

A three-fer in this shot: Lincoln's Sparrow (bottom right), Common Yellowthroat to its right (your left), and a Song Sparrow above. The closely related Song Sparrow is quite different even if superficially similar. It is "messier" in appearance - never the neatly dapper plumage of the Lincoln's, nor does it present the obvious gray and buff tones that are often so obvious with Lincoln's. Song Sparrow gestalt is different as well. It is a larger bulkier bird. The average Song Sparrow weighs about 23 grams, while a Lincoln's weighs about 17 grams. That's about 25% lighter which translates to a much different field impression.

I noticed that several Lincoln's Sparrows were drawn to the few and scattered Staghorn Sumac (Rhus typhina) treelets. This was early on my foray, and as you can see in this photo, the large flat sumac leaves were still copiously beaded with dew.

This is the same bird as above, shortly after I made the preceding shot. We've probably all heard the trendy sillyism "forest bathing" put forth by hipsters trying to get closer to nature or whatever. Well, this is real forest bathing. The Lincoln's Sparrows were bathing in dew: pushing and rubbing into the wet sumac leaves, then vigorously shaking and preening. It was really cool to watch this, and it did make me feel closer to nature.

It wasn't just Lincoln's Sparrows on my 2 hour and 15-minute immersion into the marsh. In all, I detected about 50 species of birds, including seven other sparrow species. The latter tally included a Clay-colored Sparrow, rather a rarity in this neck of the woods. Several Nashville Warblers and a Palm Warbler were working the goldenrods, and several Bobolinks passed overhead giving their melodic "pink" calls. Raucous families of Red-headed Woodpeckers made aerial sorties in between harvesting acorns in the nearby woods. At one point, I saw the whirlwind appearance of an accipiter far ahead, undoubtedly trying to whack the sparrows and warblers that I was admiring. It was just a split-second look, but now I was on point, waiting for it to reappear. A minute later, a female Sharp-shinned Hawk - a songbird's worst nightmare - shot from the shrubs and within ten feet of my head, surprising both of us. The snappy little raptor winged down the dike, then landed on the ground staring around ferociously. As nearly always happens, the songbirds fell silent and waited for the threat to disappear.

I'll try to post some other imagery from this trip later.

Friday, September 20, 2024

Mothing in a cave

 

Mothing in a cave. At our recent caterpillar safari at Highlands Nature Sanctuary, owned by the Arc of Appalachia, most of us were in the museum photographing caterpillar livestock on Sunday morning. Laura Weis had been out hiking and rushed in to tell us she had found a moth deep in a cave. We, needless to say, rushed out to see this spelunking moth. It was The Herald Moth (Scoliopteryx libatrix), which feeds on willow as a caterpillar. The cave that Laura found (photo above) it in was right above Rocky Fork, which would have plenty of willow along its banks. Highland County, Ohio, September 8, 2024.

NOTE: There are no known roosting bats in this cave. The Arc of Appalachia has a very good handle on which caves host bat roosts, and those are well-protected and human entry is forbidden.

Your narrator photographing The Herald Moth, which was in a little alcove about 40 feet back in the cave.

The gorgeous Herald Moth. It is striking and unmistakable, and I've only seen a handful. The adults overwinter, and some of them "hibernate" deep in caves.

As a bonus for going subterranean, there were plenty of Eastern Cave Long-jawed Orbweavers (Meta ovalis). This female guards her egg case, which looks like a fuzzy lightbulb. When well-illuminated, the spider reveals itself to be a colorful work of arachnid art.

Friday, September 13, 2024

Camo caterpillars and the birds that eat them

 

A Red-eyed Vireo (Vireo olivaceus) in a characteristic hunting posture. The bird is searching for its major prey, the caterpillars of moths. It has its head cocked upwards, searching the lower surfaces of the leaves above, as that's where many caterpillars hide during the day. Lepidopteran larvae - and those are OVERWHELMING moth caterpillars (not butterfly caterpillars) - are the vireo's major food source. During a long summer day, the roughly 130 million Red-eyed Vireos breeding in the U.S. and Canada consume something on the order of 4 billion caterpillars. Hard to believe but based on what is known of their foraging rate and dominant prey items, that's how the numbers shake out.

A Prothonotary Warbler (Protonotaria citrea) with a freshly harvested caterpillar (unsure of species). Almost all of the 38 warbler species that breed in eastern North America eats scads of caterpillars, and so do most groups of songbirds. So do some nonpasserine species, most notably the cuckoos. Many of these birds are migrants that winter in more southerly haunts, often in Central or South America, and migrate northward during the breeding season to exploit the eastern deciduous forest region's vast bounty of caterpillars. As this is crop is only seasonally available, many of these bird species must travel back to warmer climes for the winter - where they undoubtedly also consume great numbers of caterpillars.

If you are a caterpillar, you don't want to be grabbed and eaten by a bird. Evolutionary warfare between caterpillars and birds is probably the main driver of some incredible caterpillar camouflage. If you are a plant-eating caterpillar and can become ever more like the appearance of the plants that you feed on, the odds of surviving surely goes up. Birds are endowed with incredibly keen eyesight and are quite adept at spotting larvae. They still find plenty, and between the avifauna and all of the other predators that take out caterpillars, the survivorship can be as low as 1% in some moth species. So, every advantage that a caterpillar can get to thwart predators becomes very important.

Following are some photos, most from recent forays, that showcase examples of incredible botanical (and gall) mimicry by members of the larval crowd.

Late summer and fall foliage become dappled with color as the chlorophyll fades and leaf tissue begins dying. This plump Blinded Sphinx Moth (Paonias excaecata) caterpillar displays reddish patches that mimic autumnal foliage, in this case Hop-hornbeam (Ostrya virginiana).

This is a sister species of the caterpillar above, the Small-eyed Sphinx (Paonias myops), which also sports rusty dots that resemble necrotic leaf tissue.

This is a personal favorite of the leaf-edge mimicry crowd, a Double-toothed Prominent (Nerice bidentata). It is a specialist of elms, and in our part of the world that's almost entirely American Elm (Ulmus americana) and Red Elm (U. rubra). We find them on both of this species with roughly equal frequency. The back of the caterpillar is scalloped, much like the rough marginal serrations of elm leaves. As it eats into the leaf, the caterpillar becomes the leaf.

This is another elm specialist (mostly at least, it is also said to eat basswood), and its moniker is apropos: Elm Sphinx (Ceratomia amyntor). When at rest on the underside of an elm leaf, as above, the caterpillar typically aligns itself with the prominent midrib of the leaf. The caterpillar also has a raised stripe down the center of its back. The cat's lateral lines are arrayed at acute angles to its pseudo midrib and mirror the angled venation of the elm leaf. In effect, the caterpillar becomes a continuation of the leaf's veins.

Few can match the Checker-fringed Prominent (Schizura ipomoeae) caterpillar's ability to become one with the leaf. This one (the head is to the bottom) is consuming an old dogwood leaf and as is typical, the caterpillar is eating inwards from the leaf's edge. In essence, it becomes the leaf and spotting one of these can be quite difficult even when it is right in front of you. Sharp-eyed botanists might note the cat's scientific epithet: ipomoeae. That references a genus of morning-glories and is probably a misnomer, as this caterpillar probably never eats those plants.

Few do twig mimicry better than the caterpillar of the Dot-lined White Moth (Artace cribaria). They are virtually impossible to see as they lay plastered to twigs, despite being a hefty cat.

Another brilliant example of twig mimicry is the Yellow Slant-line Moth caterpillar (Tetracis crocallata). This is one of the inchworms in the massive Geometrid family, and many inchworms are twig mimics. When not feeding, they attach themselves to a twig of similar diameter and color, and often adopt an acute outward angle. In the case of this species, the head is jagged and pale yellow, exactly as a broken-off branch would appear.

A Redbud (Cercis canadensis) leaf, with what appears to be a raised reddish gall. Such leaf galls are commonplace, and can be formed by many organisms: bacteria, fungi, aphids, midges, wasps and others. Birds don't eat them, insofar as I know.

But wait! Closer examination shows that our leaf "gall" is not a gall at all. It is a Red-crossed Button Slug caterpillar (Tortricidia pallida). Slug moth caterpillars are fascinating as a rule, as are the "cute" little moths that they become. As caterpillars, many species appear to mimic the look of leaf anomalies such as galls, and they can be hard to spot.

This is just a tiny tip of the lepidopteran iceberg when it comes to caterpillar mimicry, much of which is presumably driven by sharp-eyed birds that attempt to feed ravenously on the caterpillar crowd.


Monday, September 9, 2024

Epic caterpillaring results in many cool finds

 

Cherry Dagger moth caterpillar (Acronicta hasta)

Shauna and I spent last weekend at the fabulous Highlands Nature Sanctuary in Highland County, Ohio, which is owned by the Arc of Appalachia. A bunch of us were there for our 12th annual "caterpillar safari", which is just a bunch of larvally-minded friends of ecology gathering to seek out the always fascinating caterpillars of moths (mostly) and butterflies (far fewer in numbers and diversity). Now is peak season for caterpillar abundance and diversity, and we prowled into the wee hours on Friday and Saturday nights, exploring interesting habitats. Most caterpillars are active nocturnally, so hunters of them must adjust their search hours accordingly.

Dozens of species of caterpillars were found and photographed, including this Cherry Dagger (Acronicta hasta). We brought lots of livestock back to the Arc's forest museum - our base camp - and from 10 am - 2 pm the public is invited in. Dozens of people got to see crazy larvae that they likely never knew existed. One should not underestimate the value of moth larvae (which the overwhelming number of caterpillars are). They are the primary organisms that convert plant matter into a digestible form of protein for birds and myriad other animals and underpin food webs.

Gray Hairstreak caterpillar (Strymon melinus)

We certainly do not ignore the occasional butterfly caterpillar that turns up, and this was a particularly interesting one. It is the caterpillar of the Gray Hairstreak (Strymon melinus), which specializes on feeding upon species in the Pea Family (Fabaceae). These cats resemble Mike & Ike candies and are tiny and easily overlooked.

This one is feeding on a tick-trefoil in the genus Desmodium. Many hikers know this group of plants by their triangular loments (fruit) that are thickly beset with stout hooked hairs. They evolved for mammalian dispersal, and that includes the clothing worn by humans. Those loments can be tough to get off and will even survive trips through the washing machine.

Here's what that Gray Hairstreak caterpillar in the previous image will (hopefully) morph into - one of our showiest butterflies. I say "hopefully" because the survivorship of caterpillars is astonishingly low. Just about everything wants to eat them and for some species of moths, at least, probably only one percent or so of caterpillars make it through the complete life cycle and to the mature reproductive stage. The rest become part of a great food chain. To compensate for such high mortality, butterflies and moths lay enormous numbers of eggs; a carpet-bombing strategy if you will.

Finally, a cool little-known thing about Gray Hairstreak butterflies. John Howard showed this to me a while back. Hairstreaks habitually rub their hind wings together, and the "tails" resemble antennae. Perhaps this pseudo face with its twitching antennae fools birds and other would-be predators who then lunge at the wrong end of the butterfly. While the hairstreak may lose parts of its hind wings, it might still escape to live another day and find a mate and reproduce.

Anyway, as John pointed out, if you can get directly behind the hairstreak and under it (that can take some effort), the lateral fringes form the illusion of orange eyes capped with long antennae, and even a frowning mouth below. Whether all of that evolved to spook visual predators I do not know, but whatever the case it certainly looks cool. And once a butterfly photographer knows this, they may find themselves spending much time attempting to get into position to get this shot.