Don’t Write Off the Bat

It was a perfect evening for a spin in the Batmobile with a team of three amateur chiroptologists. The air was warm and still when the sun went down.

After leaving the carpark, we were overtaken by every vehicle along the Colonial Parkway as we crawled at 15 mph, hugging the kerb. Fortunately, the traffic was light. It was too dark to see if the faces passing us were puzzled by the tall aerial sticking out of our sunroof or if they guessed what we were up to from the sticker on our trunk illuminated in their headlights: Bat Monitoring – Pass Safely.

Although I rarely hear bats nowadays, I love to watch their silhouettes against the last glow of a darkening sky. Their acrobatic flights look sheer joy, although I know they are to satisfy voracious appetites, twisting and turning to skim the air of mosquitoes, moths and lumbering beetles.  After years of wondering what species lived here, I now had an opportunity to find out.

The passenger sitting beside the driver held the aerial with one hand and used the other to control the tracker pad of a laptop perched in front. I watched over her shoulder as she loaded the SonoBat software.

SonoBat
All set in the Batmobile

We hadn’t gone far along the tree-lined parkway when the computer chirped. It was our first hit. A chirogram on the screen (like a sonogram) showed regular pulses as a bat called for echolocation to detect prey and avoid obstacles. A machine-learning algorithm identified the species, saved data to a spreadsheet and could mark ambiguous results, if necessary. The passenger in the seat beside me backed up results by writing on a notepad. We had detected a Red bat, named for its red fur. It was impossible to see it or any others through impenetrable night.

This was my first time for a bat positively identified while flying free in the wild. Soon, there was another chirping, then another, often in a different tone and frequency. After two hours on the road we gathered 125 recordings, mostly ascertained. The total number of individuals was, however, unknown, and we probably had duplicates because bats of a given species have the same voice. But we were more confident that seven species flew close enough to detect that night, including the Big-eared, Big brown, and Silver bat. I never knew we had so many.

chirogram fromSonoBat
Chirogram of Red bat

The software program identified calls by referencing a library of thousands of recordings of species from across the continent.  We mostly detected Red bats, a common and widespread species. The Seminole bat has a similar chirogram, but being near the northern limit of its range it was unlikely to be mistaken for the closely related species.

When I joined the survey one night last year, bats were getting more attention from conservationists and there was growing public interest in their dwindling populations from loss of habitat to human development, Insectageddon threatening their food supply, and the toll from white-nose syndrome.  They haven’t lost friends who always cared about them. But people who were indifferent before or harbored superstitions can find a better excuse for fearing them than the old myth that bats get caught in young girls’ hair.

Evidence is growing that the COVID-19 virus originated in bats before it infected humans, perhaps via an intermediate host. The species and country of origin are still unclear. Bats harbor coronaviruses to which they evolved enviable tolerance from long association and robust immunity. They have orthologs of our ACE-2 protein, a molecule with a physiologic role and widely distributed on our cells that offers the virus a gateway for infecting us by binding its spike protein.

To persecute bats as suspects of this or other zoonoses (certainly they can carry the rabies virus, like any other mammal) is no more justified than putting people in jail for spreading disease before they understood the menace or knew they were infected. Solutions to our problem lie not with the animal but in our connected world and with global travel.

Bats flying at night
Thanks to Ruth Rios on Unsplash

Bats are fascinating creatures in the web of life. They cling to familiar habitats and if left alone they help us as insect-eaters and providers of pollination services.

When contact distancing is revoked after the pandemic, I hope to board the Batmobile again to watch pulses on the glowing screen that spark imagination about the peregrinations of bats outside in the night.

Next Post: On Human Population

There’ll Be Bluebirds Over

The American composer of “There’ll be Bluebirds over the White Cliffs of Dover” either had the excuse of poetic license or didn’t know that bluebirds are absent from the British Isles. But the song became one of one of Dame Vera Lynn’s signature performances for stirring patriotic hope in 1942.

There are three species of bluebird in North America (all thrushes). Someone who grew up in Tidewater Virginia doesn’t remember seeing Eastern bluebirds here in the 1960s, probably because urban sprawl and competition from introduced species robbed them of natural cavities to make home. But no longer.

nestboxes
Male Eastern bluebird (photo: Inge Curtis)

The friendly songsters are now common in local meadows and suburban gardens thanks to human interference, sponsored by the Virginia Bluebird Society and kindly people who provide nestboxes. The best boxes are not the kind found in knickknack stores, gaily painted (for predators to find) and with a perch close to the entrance hole (to help predators look inside). Constructed of rot resistant cedar, an ideal box has a 1.5” entrance hole protected by a wire mesh predator guard and a snake guard on the pole. While these safeguards are not 100% effective, most broods reach the fledgling stage for the most dangerous days of their lives.

Bluebirds are nesting in two of our four boxes, each with five sky blue eggs. I don’t peep inside again until the chicks have flown after gorging on countless insects and arachnids brought by doting parents. Then, I clean out old nests that might harbor parasites, and usually find the lodgers have made new ones of pine straw and small sticks a few days later for a second brood. Even if I trained for months using forceps to weave the straw I doubt I could craft anything that would pass a bird’s inspection.

Our third box is still vacant and the fourth has a house wren sitting on brown speckled eggs.

Bird eggs are among the most beautiful objects in nature. They are delicate works of art, sometimes decorated with pigments as if squirted from paint guns in the oviduct on the day before laying. It is no surprise that ground-nesters have camouflaged eggs or that eggs laid further north tend to be darker to absorb more heat. We might expect cavity nesters, such as owls, kingfishers, woodpeckers, and wood ducks, would have pure white or buff eggs as coloring provides no obvious advantage. The colors of bluebird and wren eggs are among the exceptions, which goes to prove that nature hates uniformity and ruins our simple hypotheses.

Box taken over by house wrens
Adopted by house wrens

Data from over 4,500 nestboxes on 410 trails across Virginia are compiled by the Bluebird Society. Our local chapter of Master Naturalists monitors a few hundred boxes in parks and around golf courses every week between March and July. On a trail where I help to monitor 41 nestboxes, there were 63 bluebird fledglings in 2018  (a wet spring) and 97 last year, plus a few broods of chickadees and tufted titmice. Nestboxes raise thousands of extra birds.

This year the coronavirus pandemic disrupted our survey, but not the breeding season, which may even benefit from less human traffic and noise. But human nature doesn’t seem to change as I heard that three of our boxes have been vandalized. Who could do that to bluebirds?

 

Pepysing back at the 1665-66 plague of London

I aimed for a weekly post about the health of the natural world, but here I am dwelling on coronavirus again. Is anyone undistracted by this pandemic?

This time I dusted off my copies of Samuel Pepys diaries in which he recorded the bubonic plague in the city I grew up in. Londoners were familiar with the scourge. The Black Death carried off most of the population across Europe in the 14th century and made other appearances. Although believed to be carried in the air (‘miasma’), human contact was a known agency too. Inbound merchant vessels had to rest at anchor for 40 days before disembarking (a number straight from the Bible). Plagues then took months to sweep across the known world in merchant sailing ships as we became more connected by trade, but it only takes a few hours or days by air travel today.

Pepys wrote in August 31, 1665: “the plague everywhere through the kingdom almost. Every day sadder and sadder news of its increase. In the City died this week … 6,102 of the plague. But it is feared the number of the dead this week is near 10,000”. He had little confidence in statistics because the poor were often unrecorded and Quakers forbade tolling the bell for their losses. Nor will the true number of coronavirus deaths be known for a long time.

Two weeks later: “To hear that poor Payne, my waiter, hath buried a child, and is dying himself. To hear that a labourer I sent but the other day to Dagenhams is dead of the plague and one of my watermen …” Epidemic is merely numbers until its meaning is wrought in suffering people you know and care about. Willful ignorance and denial of science we currently witness in the news will surely be tested with the fire of personal tragedies to come.

Church on the hillA shipment of cloth from London to a tailor in Eyam, a small village near Sheffield, carried infected fleas in 1665. Dreaded buboes erupting with pus appeared on the skin of villagers. The Eyam community led by an Anglican priest is hailed as an example of self-sacrifice where quarantine was imposed to avoid spreading the contagion outside.

Beautiful myths grow up where facts are scarce. The priest sent his children away and the poor could not afford to go. But it is a fact that only a quarter survived, and maybe the odds in neighboring villages benefitted from ‘lockdown’. According to a math model, quarantine may have made matters worse for Eyam by prohibiting dispersal if closer contact led to a more deadly pneumonic (pulmonary) plague. If there is a hero in the story, it is the priest’s wife because she stayed and died.

We constantly ask how the current ‘plague’ will end, and when?  In Eyam it burned out by running out of victims (from herd immunity?), but no one imagined it would take a literal fire in London.

Pepys wrote on September 2 of the following year: “With my heart full of trouble, to the Lieutenant of the Tower (of London), who tells me that it began this morning in the King’s baker’s house in Pudding-lane, and that it hath burned down St. Magnus’s Church and most part of Fish Street already … and did tell the King (Charles II) and the Duke of York what I saw; and that, unless his Majesty did command houses to be pulled down, nothing could stop the fire.” It seemed perverse to add to the physical and economic destruction but in the end was the best policy.

Sometimes we have been lucky in history with leaders who rose to the challenge of crises with coordinated, compassionate and effective responses. This time we have seen dithering politicians scared that bold responses might dent their standing and blind to the bigger picture. This coronavirus emergency is terrible and a vaccine is an urgent goal, but unless its roots in careless stewardship of nature are acknowledged the ancient cycle of plagues will be repeated, because everything is connected.