Cave Swallow Express

Cave Swallow (Petrochelidon fulva)

One of my favourite walking routes is a 5 km stretch of Lake Erie coast, along beaches, over dunes, past wetlands and scrubby bush, which even in December, can produce a good diversity of birds, including fantastic counts of waterfowl. Sometimes, this walk offers up a particularly nice surprise, like the one that came in the form of three Cave Swallows (Petrochelidon fulva), just the other day. Cave Swallows are rare in Ontario, but they do occur nearly every autumn, and the reasons behind their late-season appearance are still a little unclear, but is a probably a combination of factors, including far-ranging weather systems, population ecology and life history traits.

Usually, Cave Swallows begin to appear in Ontario in late October through November, with some birds lingering (or even arriving) as late as December, when the weather allows. Almost all of Ontario's records are from the north shores of Lakes Erie and Ontario, with a few scattered observations elsewhere. Movements into Ontario seem to be almost invariably preceded by strong southerly winds, sometimes in the form of hurricanes and tropical storms, or as more subdued systems which channel warm air out of the southern United States and into the Great Lakes basin. In late fall and even early winter, when southern winds are blowing, it's time to start looking for Cave Swallows. It's not just Ontario that receives these apparent reverse migrations of swallows, the southern Atlantic states, for example, also experience such events.

But why is it the Cave Swallow, of all the possible species, that gets blown north each fall? There are likely a number of factors at work, the first being the phenomenal population increase this species has undergone in Texas since its first breeding record in 1915. Texas's Cave Swallows have increased their breeding range by an estimated 898% since 1957, with concomitant increases in the numbers of both breeding and overwintering birds, particularly in the 1990's. Ontario records may reflect the assent of Cave Swallows, to some degree; the first record of Cave Swallows in Ontario was in 1989, and near-annual autumn movements began in 1998. Species that experience such explosive population growth and range expansion, also seem to be most prone to producing vagrants, in part because young birds may be disperse widely in search of new, less densely populated breeding sites.

There are also life history traits that may mean Cave Swallows are particularly good candidates for vagrancy. Being aerialists, swallows are more likely than other birds, to be sucked into weather systems. Because they are such gifted fliers, Cave Swallows could potentially ride systems longer than other species, which may need to drop out to rest before reaching the Great Lakes. That's not to say that other species don't arrive as vagrants in association with the same kinds of weather patterns that bring the swallows. Currently, there is a western flycatcher (Empidonax sp) in Ohio, and a Vermilion Flycatcher (Pyrocephalus rubinus), a Bullock's Oriole (Icterus bullockii) and a couple of Mountain Bluebirds (Sialia currucoides) in Ontario, plus a Black-throated Grey Warbler (Setophaga nigrescens) in western Quebec. These species could have all been brought north on the same weather systems that have been shuttling Cave Swallows into the Great Lakes basin this fall. Birders should use Cave Swallows as an alert system: when the Cave Swallow Express rolls in, there may other rarities on board.

BioBrevia: New Birding Record

Rufous Motmot (Baryphthengus martii)

Photo: Philina English

A team of birders in Ecuador has established a new world record: they've seen 431 species of birds in 24 hours, that's more than any other team has managed in a single day! George Paul has put together a nice article about this record (with more to come) and the history of the Global Big Day on the American Birding Association blog.

BioBrevia: Ancient Aesthetics

Han Shan

Illustration: Yan Hui

Ever since I discovered Gary Snyder's and Bill Porter's (aka Red Cloud) translations of the hermit-poet Han Shan's esoteric works, I've had a fascination with the natural imagery and aesthetics of ancient Chinese poetry. Or, at least the English translations of it. Here's a short a piece from Orion that won't be lost on fans of this remarkable art form.

BioBrevia: Finlandia

Osprey (Pandion haliaetus)

Photo: NASA (Wikimedia Commons)

 

You don't have to be a fan of classical music to appreciate this wonderful celebration of Nordic nature, set to Jean Sibelius's dramatic tone poem Finlandia, Op. 26. To me, a Canadian, Finland's wilderness of spruces, pines, rocks and lakes, looks very much like home. In fact, all of the animals featured in this video, aside from the Siberian Flying Squirrel (Pteromys volans), are shared between Finland and Canada: Grizzly Bear (Ursus arctos), Caribou (Rangifer tarandus), Common Goldeneye (Bucephala clangula), Red-throated Loon (Gavia stellata), Osprey (Pandion haliaetus) and Common Raven (Corvus corax).

BioBrevia: Another New Atlantic Forest Amphibian

Dendropsophus bromeliaceus

Photos: From Ferreira et al 2015 (Creative Commons Attribution 4.0)

Brazil's Atlantic Forest, which thanks to its more famous counterpart, the Amazon Rainforest, just doesn't get the attention it deserves, at least not from the general public. Luckily, the Atlantic Forest's incredible biodiversity hasn't been lost on biologists though, who continue working toward unravelling its mysteries. Not too long ago, I posted a note on the three new toad species that were described from the Atlantic Forest. All of those species were bromeligenous, that is to say they, like the Golden Rocket Frog (Anomaloglossus beebei) I've previously written about, breed in little pools of water that collect in bromeliads. A new paper in PLOS ONE by Ferreira et al, introduces yet another newly described phytotelm-breeding species from the Atlantic Forest. To meet the treefrog Dendropsophus bromeliaceus read the paper; here's the abstract, to get you started:

We describe a new treefrog species of Dendropsophus collected on rocky outcrops in the Brazilian Atlantic Forest. Ecologically, the new species can be distinguished from all known congeners by having a larval phase associated with rainwater accumulated in bromeliad phytotelms instead of temporary or lentic water bodies. Phylogenetic analysis based on molecular data confirms that the new species is a member of Dendropsophus; our analysis does not assign it to any recognized species group in the genus. Morphologically, based on comparison with the 96 known congeners, the new species is diagnosed by its small size, framed dorsal color pattern, and short webbing between toes IV-V. The advertisement call is composed of a moderate-pitched two-note call (~5 kHz). The territorial call contains more notes and pulses than the advertisement call. Field observations suggest that this new bromeligenous species uses a variety of bromeliad species to breed in, and may be both territorial and exhibit male parental care. (Reproduced under Creative Commons Attribution 4.0).

BioBrevia: A Bird's-Eye View of Sockeyes

Spawning Sockeye Salmon (Oncorhynchus nerka)

Photo: William Rosmus (Wikimedia Commons)

Photographer Jason Ching gives us a bird's-eye view of a big Sockeye Salmon (Oncorhynchus nerka) run on Lake Iliamna, Alaska’s largest lake. The imagery is beautiful, the fish abundant, and the resulting temptation to go see the run for oneself is real. Check out the video here.

BioBrevia: The Furthest South a Bird Can Go

South Polar Skua (Stercorarius maccormicki)

Illustration: Joseph Smit (Wikimedia Commons)

Here's an interesting meditation of sorts, from Frontiers in Ecology, on the only bird species that's ever been recorded at the South Pole: the aptly named and intrepid South Polar Skua (Stercorarius maccormicki).

BioBrevia: Hope for the Old Fashion Field Naturalist

Illustration: Philip Henry Gosse 

This brief article from Science, Explosion in new Dragonfly Species Results in Animals Named after Gorillas, Pink Floyd, and the accompanying presentation, are great inspiration for would-be naturalist-explorers. A small team recently described 60 new species of dragonflies and damselflies from west and central Africa. All of these species were recognized in the field before they were diagnosed using genetics in the lab, demonstrating that an abundance of new species still await discovery the old fashioned way, by simply getting out in the field and knowing your stuff. The actual journal article in which the new species are described is available from Odonatologica.

BioBrevia: New Species of Toads from Brazil

Melanophryniscus biancae.
Photo: from Bornschein et al 2015 (Creative Commons Attribution 4.0) 

A newly published paper in PLOS One by Bornschein et al entitled Three New Species of Phytotelm-Breeding Melanophryniscus from the Atlantic Rainforest of Southern Brazil (Anura: Bufonidae), brings to light some exciting discoveries in a rapidly vanishing habitat. Here's the abstract:
 

Three new species of Melanophryniscus are described from the Serra do Mar mountain range of the state of Santa Catarina, southern Brazil. All species are found at intermediate to high altitudes and share phytotelm-breeding as their reproductive strategy. The new species are distinguished from other phytotelm-breeding Melanophryniscus based on different combinations of the following traits: snout-vent length, presence of white and/or yellow spots on forearms, mouth, belly and cloaca, pattern and arrangement of warts, and presence and number of corneous spines. The discovery of these species in a rather restricted geographical area suggests that the diversity of phytotelm-breeding species of Melanophryniscus might be severely underestimated. The conservation status of these species is of particular concern, given that one of them is at risk of extinction not only due to its restricted habitat, but also because of anthropogenic disturbances. (Reproduced under Creative Commons Attribution 4.0).

Columbine Graveyards

Serpentine Columbine (Aquilegia eximia)

Photo: David A. Hofmann (Creative Commons)

The oak savannah and Chamise (Adenostoma fasciculatum) chaparral of California's North Coast Ranges, are interrupted here and there by a unique and altogether surprising floral community: plants that grow on poison. In this case, the poison is serpentine, rocks that are so rich in magnesium and iron that they, and their associated soils, are toxic to most plants. Most, but not all.

There are some plants that can grow on serpentine deposits and many of those are rare and endemic, not to mention highly adapted, making serpentine flora one of a most intriguing element in California's generous biological endowment. Among the most exquisite serpentine plants is Serpentine Columbine (Aquilegia eximia), which displays large red and yellow flowers to attract the attention of pollinators. In addition to pollinators, Serpentine Columbine attracts great many other insects, but for a totally different reason.

Plants attract animals to help them with all kinds of tasks; the two most obvious, of course, are pollination and seed dispersal. Pollinators are attracted by scents and visually stimulating flowers. Take the elaborate deceptions of the Fly Orchid (Ophyrys insectifera), which wafts bee pheromone-like scents from its bee-shaped flowers. Real bees come not in search of pollen or nectar, as they might at a more conventional flower, but instead they come to mate with the lookalike blossom, in the process getting coated in pollen. The bees pollinate the next orchid they visit in another misguided hope for sex.

Some plants are entirely dependent on animals for dispersing their seeds. In the Rocky Mountains, Clark's Nutcrackers (Nucifraga columbiana) are the near-exclusive disperser of Whitebark Pine (Pinus albicaulis) seeds, transporting them great distances and planting them in suitable habitats.

Examples of animal pollinators and seed dispersers are virtually limitless, but there are lots of other reasons for plants to attract animals. Sometimes it's to eat them. Venus's Flytrap (Dionaea muscipula), is probably the most dramatic of the so-called carnivorous plants, capturing and later digesting insects and even small frogs between snap tap-like leaves. Even the ubiquitous Field Thistle (Cirsium discolor) may capture insects using sticky secretions on its flowers; those same secretions act as digestive enzymes, digesting stuck insects and providing an unusual food source, at least among thistles species.

Other plants feed off animals in more passive ways. The impressive Queen of the Andes (Puya raimondii) offers paramo birds a safe haven among its hooked leaves in exchange for the highly nutritious droppings the birds leave behind. As an added benefit to the plant, a bird occassionally gets hooked among the thorny leaves, dying and providing an even richer source of nutrients for the giant bromeliad.

Some plants attract animals to help them battle damaging herbivores. Azteca ants are provided with living spaces in Ceropia trees and are fed from extrafloral necataries, in exchange for doing battle against caterpillars and other damaging herbivores. Providing shelter and nectar is a pretty conventional way of attracting helpful predators, but there are a few plants, including the Serpentine Columbine, that attract protective insects in a completely different way, and that's by essentially becoming arthropod graveyards.

Serpentine Columbine stems are covered in glandular hair-like trichomes, making them very sticky. So sticky, that they trap insects by the dozens. These trapped insects in turn attract predatory arthropods. The predators come to dispatch trapped living insects or to feed on the corpses of those that have already died. The predators are called upon to primarily combat caterpillars of the Darker Spotted Straw Moth (Heliothis phloxiphaga), which feed on the leaves, buds and even the flowers. The columbine's glandular hairs seem to be of little use in combating this caterpillar, so the plants rally Checker-rimmed Bugs (Pselliopus spinicollis), other true bugs (Order Hemiptera) and even the occasional crab spider (Mecaphesa spp), to help stavse off assault. Between meals of caterpillar, these predators feast on the stuck insects. This buffet style call to arms seems to be effective, columbines with more stuck insects (thus more helpful predators) usually experience greater reproductive success.

The insects that Serpentine Columbines capture aren't, for the most part, pollinators or herbivores that accidentally become stuck, but instead appear to be actively attracted by the plants through some kind of chemical signal. What exactly that signal is remains unclear, but it appears that Serpentine Columbine is the only plant so far known to actively attract insects in this way. Yet another remarkable find from the fascinating serpentine deposits of northern California!