Category Archives: Natural History

Journey into the Heart of Nicaragua: Parque Nacional Saslaya

In northeastern Nicaragua there is a rainforest-clad mountain that has seldom been visited by scientists, or anyone for that matter. It is called Parque Nacional (PN) Saslaya, and it is one of the last places in Central America where the Jaguar is still king, where undisturbed primary rainforest extends along an elevational gradient of over 1000 m, culminating in elfin cloud forest at the mountain’s highest reaches.

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Tropical forests once covered Nicaragua like a blanket, but modern satellite imagery reveals a country that was largely denuded of its forest cover in the last century. Not surprisingly, the highest quality forest tracts that remain are found in the North and South Caribbean Autonomous Regions (RACN and RACS, respectively), where infrastructure is underdeveloped (relative to the western half of the country) and about 300,000 indigenous people, descendants of the Pre-Colombian Rama, Mayagna, and Miskitu cultures, still persist in rural communities.

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PN Saslaya straddles the border of RACN and Jinotega, and it stands out like the proverbial sore thumb in satellite imagery. Several settlements were created along its boundaries in the years after the Nicaraguan Revolution (1978–79) and subsequent Contra War (1980s), but there are no indigenous people in the park. The people here, and in the nearby town of Siuna, are miners, cattle ranchers, and farmers. A recent wave of monoculture teak and coffee plantations in the area has been rapidly homogenizing the landscape. The only evidence of the extensive humid forests that once grew there, are large epiphytes still clinging to the upper branches of the few (now solitary) old growth trees that were spared the axe on account of their singular beauty or location. The saving grace of PN Saslaya has been its inaccessibility, and for now it remains one of the last strongholds of primeval rainforest in Central America.

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In April 2017, we mounted an expedition to PN Saslaya, to collect the first specimens of birds and their associated parasites from the region. Our team included, representing the Academy of Natural Sciences of Drexel University (ANSP), myself and colleague Therese Catanach (right in above pic), a post-doctoral researcher who studies the genomes of bird lice and their hosts; representing the University of Kansas, veteran field ornithologist Mark Robbins (center), collections manager at the University of Kansas (KU) Biodiversity Institute, and KU graduate student Jack Hruska (left), who grew up in Nicaragua and has broad interests in bird systematics, biogeography and behavior. In Nicaragua, we teamed up with ornithologist and tour guide Alexander Acosta Anton, rented a 4×4 pickup truck, and headed off across the country in search of adventure, which we found.

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The only scientific surveys of the park’s avifauna to date, are those of Liliana Chavarria Duriaux and Georges Duriaux, intrepid Nicaraguan ornithologists who made nine (!) expeditions into PN Saslaya over the last decade, literally cutting a trail to the cloud forest at 1400m with machetes! They have produced an impressive checklist of over 300 species known to inhabit the park (L. C. and G. Duriaux, pers. comm.), but to date no physical specimens had been collected for genetic and other analyses. We collected data-rich specimens that include frozen tissues for genetic analysis, blood slides (fixed in ethanol) for studying haemosporidians like avian malaria, ectoparasites like lice, ticks and mites (preserved in ethanol), over 400 audio recordings, and numerous census surveys (available on eBird.org), in addition to the study skins prepared for the museum collections at ANSP and KU. These data will survive for hundreds of years, and enable us to assess the unique value of the biodiversity of PN Saslaya, and in so doing, effectively advocate for its conservation.

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Swainson’s Thrush (Catharus ustulatus swainsoni). This species was common around the Río Labú camp from 8–16 April. Several individuals were heard singing, but at much lower volume than during their breeding season in North America.

PN Saslaya is physically and logistically difficult to access, and because there is a history of land-use conflicts (typically involving people illegally removing resources from the park), all visitors are required to have a security escort. It took us several days, and multiple trips to both the Siuna police station and military base (El Batallón Ecológico), to make the necessary arrangements. Our plan was to establish a base camp on the west bank of the Río Labú, about 6 hours hike into the park from the nearest road, where we would work for 10 days (9 nights). In addition to our military escort, we would hire a team of people from the nearby community of Rosa Grande, to porter our equipment to base camp, and arrange for them to return again on the 9th day to assist with our extraction. We stuck to the plan, and it was successful.

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The hike from Rosa Grande was hot and humid, ~3.5 km of fincas, crop fields, and scrubby secondary growth forest, to the park border at 320 m elevation. Already the topography of the trail ahead was evident: a lot of rapid gains and losses in elevation, as the single-file footpath meandered its way through the ravines cut but the myriad tributaries that fed the Río Labú. As we continued into the park, the forest transitioned into primary humid rainforest. Howler monkeys called out in the distance as we paused at the park boundary, and a Lesser Greenlet (Pachysylvia decurtata) sang from the sub-canopy. Therese and I watched a jaguarundi (Puma yagouaroundi) cross a log about 15 m away, while we paused on the trail for a moment to catch our breath. It clearly knew that we were there, but it did not seem concerned by our presence. So few people venture that far into the park each year, that it is conceivable that it was that individual’s first encounter with a human.

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White-whiskered Puffbird (Malacoptila panamensis)

Our team of eight soldiers were on orders to keep us safe, and probably to make sure that we did not get ourselves into any trouble. They took that charge very seriously, sending scouts out ahead of our group, and leaving one behind to ensure that we weren’t flanked. When we finally arrived at the site of our base camp, as the sun was setting and the forest interior already quite dim, we scrambled to get our tents set up before dark. Beginning that night, the soldiers began a 24/7 patrol of the camp, taking turns on the night shift duty. I occasionally left my tent in the middle of the night (~0200) to relieve myself, and couldn’t resist the urge to joke with the patrol, asking him whether he had heard any funny noises. During the day, the soldiers toiled about camp, building thatch-roof huts to cover their hammocks, and trying to get a radio antenna high enough in the tree tops to establish contact with the base. One of the soldiers captured a baby Central American Agouti (Dasyprocta punctata), and kept it for a pet for a couple days until it escaped.

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To be continued…

A closer look at the wing of Swainson’s Thrush (Catharus ustulatus swainsoni) in First Basic plumage

Like other migratory Catharus species, juvenile Swainson’s Thrushes (Catharus ustulatus swainsoni) molt into a ‘First Basic’ plumage at the end of their first summer, which they wear for one year before attaining their ‘Adult Basic’ plumage. The partial molt that results in First Basic plumage includes some or all of the median coverts (the little olive feathers above the numbered row), and up to five of the (inner) greater coverts, which are numbered 1–9 in the image. In this case, the bird molted only one greater covert: #1, the fresh olive covert without a buffy tip. The retained juvenile coverts (2–9) are paler and more brown, and numbers 2–6 end with a buffy tip. This is called a molt limit, and it helps us to figure out the age of a bird. For all the juicy details of molt limits in North American passerines, check out Peter Pyle’s Identification Guide to North American Birds, Part 1, 1997.

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This bird died in a window collision in Montgomery Co., PA, in late September 2016. After taking the photo, I prepared the specimen for the Ornithology Collection at the Academy of Natural Sciences of Drexel University. Legend: primaries (P1–8); secondaries (S1–9). The 9th and reduced 10th primaries are not visible in the photo.

Catching Anacondas

Some things that are done impulsively, and perhaps recklessly when considered afterward, make for the best memories. I don’t know if I would do this again, if given the opportunity, but I am glad that I did it once. The snake was not harmed, and thankfully neither was I, and after the experience I have a much deeper reverence for species and other large snakes, and their incredible constrictive power. Few animals can match the Green Anaconda; I could barely manage to control this one, which was not yet full grown. This encounter happened in the Llanos of Venezuela in 2007, at Hato Masaguaral, Guarico. My video of an anaconda constricting a Spectacled Caiman was presumably of a different individual snake than the one shown in the videos below. All three were filmed within 0.5 km of each other.

 

Smooth-billed Ani — in Philadelphia!

Like most birders, Philadelphians get excited about a rare bird. With over 250 years of bird records from Philadelphia, the birthplace of American ornithology, there are very few species that have been detected in the city only once—the rarest of the rare.

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ANSP 24271. Ornithology Department, Academy of Natural Sciences of Drexel University (Photo: M. Halley)

One of the most mind-boggling records is actually not well known by birders today—a Smooth-billed Ani (Crotophaga ani) was collected in the 1850s by John Krider, apparently on an island in the Delaware River near Kensington, Philadelphia. Today, and during Krider’s time as well (Baird 1860), the nearest breeding ground of this Neotropical cuckoo-relative (Cuculidae) is in southern Florida. Otherwise, the species is a widely distributed breeder in the tropical and subtropical savannas of the Caribbean, Central and South America.

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ANSP 24271, label verbatim: “Shot on Peters Is. Delaware Riv. opp. Kensington Pa. J Krider Coll.” (Photo by M. Halley)

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Closeup of Charles Ellet Jr.’s (1843) map of Philadelphia, showing the location of Petty’s Island in the Delaware River.

However, the island opposite Kensington is called Petty Island today (not Peters Island, which is actually in the Schuylkill River near Montgomery Dr.), and during Krider’s time it was called Petty’s Island — so something here is amiss. To confuse things further, in Krider’s (1879:16–17) published account there is no mention of the island, and it actually implies that the bird was collected in the expansive meadows of South Philadelphia (i.e., Passyunk, Moyamensing), a habitat that would later be consumed by urban development: “The Ani is a southern bird. I shot one specimen in the month of September, in the meadows below the built-up part of the City of Philadelphia. It was flying in company with a flock of rusty Gracles [probably Common Grackle Quiscalus quiscala, or perhaps Rusty Blackbird Euphagus carolinus]; the specimen is now in the Academy of Natural Sciences.”

So the precise locality where the bird was collected is uncertain, because Krider’s (1879) account disagrees with the information on the (not original) specimen label. Nevertheless, it was evidently collected in one of the marshes along the Delaware River in Philadelphia.

Spencer Baird (1860:73) wrote: “A Crotophaga, killed near Philadelphia, and now in the collection of the Philadelphia Academy, appears to be a typical C. ani (as described by Burmeister) in the smoothness of the bill and other peculiarities. It is decidedly smaller than rugirostris, the culmen straight at its highest point, the anterior extremities of this nearly straight portion anterior to the nostril. The colors are, however, almost precisely the same with those of rugirostris. Length, 12 inches: wing, 6.10; tail, 7.75; tarsus, 1.25; chord of culmen, 1.15.”

References
Baird, S. F. 1860. The birds of North America: the descriptions of species based chiefly on the collections in the Museum of the Smithsonian Institution. Philadelphia: J.B. Lippincott & Co.
Krider, J. 1879. Forty years notes of a field ornithologist. Philadelphia: Joseph H. Weston.

“Winter” specimens of Swainson’s Thrush in eastern North America

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ANSP193361 — C. u. swainsoni, collected by J.H. Weber on 3/3/1904. Photo: Matthew R. Halley

I came across a specimen of Swainson’s Thrush (Catharus ustulatus swainsoni) in the ornithology collection of the Academy of Natural Sciences (ANSP193361) that was collected by J. H. Weber in Fort Lee, New Jersey on March 3, 1904! This sparked my curiosity because this taxon, considered a subspecies by most authorities but a species by the Brazilians (Piacentini et al. 2015), spends the winter in South America and does not typically arrive in North America until April. This set me on a brief search for other North American “winter” specimens of C. u. swainsoni. For the purpose of my investigation, I was hesitant to rely on sight records, because it is easy to misidentify these thrushes in the field (trust me), and eastern Hermit Thrushes C. guttatus faxoni are normal winter residents in these regions. For these reasons, I wanted hard evidence, and a search of major specimen collections did the trick.

I looked for specimens collected during November through March. A query on VertNet.org returned 800 specimen records from that time period, of which 24 were collected in North America east of the Mississippi River. Of those, 9 were erroneous or dubious (e.g., several records had the date 1/1, the default of some databases when a date field is left blank). After separating the wheat from the chaff, I managed to uncover 15 (apparently) legitimate “winter” records, which I plotted alongside an eBird chart compiled from three “Bird Conservation Regions” that cover a large portion of the ‘transient zone’, i.e., in between the breeding and wintering grounds of C. u. swainsoni. Interestingly, the specimen that started my search (ANSP193361) was actually one of three taken by J. H. Weber in Fort Lee, New Jersey—20% of the “winter” C. u. swainsoni specimens taken in eastern North America were found at the same place by the same guy!

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The orange curves in the figure show the annual cycle (in total # of birds detected) from the perspective of birders in the ‘transient zone’. There is a sharp decline in autumn (far right of the graph), and detections typically cease by the end of October. The birds are then absent for the next five months (they are “on holiday” in South America). Then, the spring migration brings a rapid increase in detections in early- and mid-April, as Swainson’s Thrushes migrate northward to their breeding grounds.

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C. u. swainsoni in the ‘transient zone’. Photo: Matthew R. Halley.

Three of the “winter” specimens were collected in early November, and can easily be attributed to late departures, and not overwintering birds (MCZ338962, UMMZ234592, UWBM86964). To my knowledge, there have been no specimens collected during December, and only one legitimate record from January, a specimen collected in Brown Co., Wisconsin (FMNH351309); and that specimen was collected in late January (the 21st). Two specimens from mid- and late-February were collected in Frederick Co., Maryland (UWBM 38236), and New Haven Co., Connecticut (YPM ORN 002630), respectively. The remaining 9 specimens were taken in March, one month before the expected arrival of the species in North America, and so can be explained as early arrivals. Indeed, given the distribution of these “winter” specimens, clustered near the tails of the eBird distributions, there is very little to suggest that any of them were actually over-wintering individuals. Rather, they seem to be aberrant individuals with early or late departure or arrival dates, outliers way out on the tail ends of the normal distribution, but still a part of that distribution. However much I might like to think one of these Swainson’s Thrush specimens was an over-wintering bird, the null hypothesis is that they are just super late/early migrants (i.e., a migrant with wacky timing seems more plausible than a bird that ceased to migrate altogether). At present, the weight of the evidence is not enough to reject the null.

So no—sorry to get you excited, but at the present moment there is no evidence of a Swainson’s Thrush wintering in North America. Many thanks to the folks at ebird.org and VertNet.org, and to the many collectors, preparators, and curators of the collections.

[UPDATE, 12/21/2016: I recently came across an article in Cassinia (62:65) in which Keith Russell reported a Swainson’s Thrush at Cape May Courthouse, NJ, on December 24, 1985! Identification was corroborated by Bob Ridgley. This indeed is a good candidate for an individual *actually* overwintering in this region, but I do not know if it was seen in subsequent weeks.]

Genetic sampling of Townsend’s 1835 type specimens of Catharus

In 1834, pioneer naturalists Thomas Nuttall (1786–1859) and John Kirk Townsend (1809–51) ventured westward with the second expedition of Nathaniel Jarvis Wyeth (1802–56), across the Rocky Mountains and eventually to the mouth of the Columbia River. The trip was a huge success, and Townsend discovered numerous bird species that were previously unknown to science. In 1836, Townsend opted to venture farther west to the Sandwich Islands (Hawaii), and so entrusted his bird collection to Nuttall, who returned with it to the Academy of Natural Sciences of Philadelphia. There, the specimens were eagerly awaited by John James Audubon (1785–1851), who was preparing the final plates for The Birds of America:

“Dr Townsend’s collection was at Philadelphia; my anxiety to examine his specimens was extreme…Having obtained access to the collection I turned over and over the new and rare species but he [Townsend] was absent at Fort Vancouver on the shores of the Columbia River, Thomas Nuttall had not yet come from Boston and loud murmurs were uttered by the soidisant friends of science, who objected to my seeing, much less portraying and describing, these valuable relics of birds, many of which had not yet been introduced into our fauna.” Audubon (1838:xi)

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Paralectotype of Catharus guttatus nanus, collected by Townsend and described by Audubon (1839)

Among the specimens in the collection were two thrushes new to science, that we now know as Catharus ustulatus Nuttall (i.e., Swainson’s Thrush) and Catharus guttatus nanus Audubon (now considered a subspecies of Hermit Thrush). The prepared specimens are still in the Academy collection. See my previous post about the discovery and description of the C. ustulatus type.

Today, I harvested a tiny sample of skin from the C. ustulatus holotype, and a paralectotype of C. g. nanus—both collected by Townsend during the Wyeth expedition. The samples will be prepared and submitted for DNA sequencing—genetic data that will be included in my dissertation work on the systematics, evolution, and taxonomy of the genus Catharus. These two type specimens, which were examined 180 years ago by Townsend, Nuttall, and Audubon, will now be used again to clarify the ancestry and taxonomy of these species. I hope that, if they were alive today, Townsend and the rest would approve!

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Collecting skin tissue for DNA sequencing from the holotype of Catharus ustulatus (ANSP #23644)—collected by Townsend and described by Nuttall (1840). Courtesy of the Academy of Natural Sciences of Drexel University. Photo: Steve Miller.

 

 

My first encounter with a Newfoundland Veery (Catharus fuscescens fuliginosus)

In 1900, a young ornithologist from Massachusetts named Reginald Heber Howe, Jr., then just 25 years of age, described a new subspecies of the Veery (Catharus fuscescens) from the mountains of southwestern Newfoundland. He named it fuliginosa, meaning “sooty”, which was later gender-corrected to fuliginosus when the species was moved from Hylocichla to Catharus. Howe (1900) wrote:

“Subspecific characters.—Size slightly larger. Upper parts especially on the head, distinctly brownish, much darker and not of the tawny shade of typical fuscescens, and lacking the greenish tinge of salicicola. Throat, lores, and upper breast suffused with buff, though perhaps less so than in fuscescens (in salicicola buff is practically absent), the upper breast and usually also the throat spotted heavily with broad arrow-shaped brown markings suggesting very strongly the throat and breast of H. u. swainsonii. The breast markings of both fuscescens and salicicola are narrow and more penciled and lighter in shade. Bill darker and heavier.”

I encountered the Newfoundland Veery in the Table Mountains of southwest Newfoundland, during a 2015 expedition to study its close relative, the Gray-cheeked Thrush (C. minimus)(see previous posts). We found C. fuscescens singing along the starlight trail, in a mixed deciduous/coniferous habitat that was also utilized by another close relative Swainson’s Thrush (C. ustulatus swainsoni). In the video above, notice the Swainson’s Thrush singing in the background of the video!  We captured both species in our mist nets, including three Newfoundland Veeries. One of the females we captured had an egg developing inside of her, confirming breeding of this species at the site. I also made audio recordings of two males at this site, and uploaded them to xeno-canto (http://www.xeno-canto.org/298771; http://www.xeno-canto.org/325285), where they represent the first recordings of C. fuscescens from Newfoundland in that archive.

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Forest habitat in the Table Mountains where C. ustulatus swainsoni and C. fuscescens fuliginosus breed syntopically. We did not detect C. minimus at this site, but they may have been breeding at slightly higher elevation than our nets (see Marshall 2000).

Remarkably, almost nothing has been published about this race of the Veery since Howe (1900) first described it. All specimens from Newfoundland are typically labeled fuliginosus by collectors, although the characters noted by Howe (e.g., brownish coloration of the dorsal plumage) may be prone to foxing and other post-mortem color change. Indeed, it remains to be seen whether fuliginosus is actually a diagnosable race, since its description more than a century ago was based on largely subjective evaluations of color that would be insufficient to justify a new taxon today. More research will be needed to determine the evolutionary history of this interesting brownish race, including the location and connectivity of its wintering area(s).

Literature Cited

Howe, R. H. 1900. A new subspecies of the genus Hylocichla. Auk 17, 270–271.

Marshall, J. T. 2000. The Gray-Cheeked Thrush, Catharus minimus and its New England Subspecies, Bicknell’s Thrush, Catharus minimus bicknelli. Nuttall Ornithological Club, pp. 136.