Letters from Gilbert: 3
On this day in 1771 Gilbert White, whose 300th anniversary we celebrate this year, was thinking about migration. Exactly 245 years later I visited his home on my own spring journey.
April 14, 1771, Selborne. Swallow appears as last year amidst frost & snow!
Between 1768 and his death in 1793 Gilbert White kept a diary, his Naturalist’s Journal, and on this day he celebrated one of the defining moments of the spring. On April 14 2016 I had reached Selborne on my The Long Spring journeys. At The Wakes, the house White grew up in and returned to when he inherited it from his father in 1758, the original manuscript of the Natural History was displayed behind glass in an upstairs room It was open at a letter to Daines Barrington dated March 19 1772, when White was recalling the previous year’s appearance of the first swallow, and anticipating the same event sometime in the weeks to come.
I am more & more induced to believe that many of the swallow kind do not depart from this island; but lay themselves up in holes & caverns; & do, insect-like and bat-like, come forth at mild times, & then retire again to their latebræ. ….. And I am more of this opinion from what I have remarked during some of our late springs, that though some swallows did make their appearance about the usual time, viz., the thirteenth or fourteenth of April, yet meeting with an harsh reception, & blustering cold N+E: winds, they immediately withdrew, absconding for several days, till the weather gave them better encouragement.
White and Barrington were continuing a debate that was at least two thousand years old, since Aristotle wrote in the History of Animals in 350 BCE that many birds do not migrate but go into hiding. Aristotle appears to have based this view on reports of swallows being found alive, but without feathers, in holes during the winter. In the course of the correspondence, White is revealed as a firm believer in migration, unlike Barrington, but not a complete disbeliever in the possibility that some birds may hibernate as well.
Since then, two centuries of ringing and, lately, satellite studies have shone ever more light on birds’ extraordinary movements. Aristotle’s belief in featherless birds spending the winter in clefts in the rock seems consigned to the realm of fantasy. But in 2016 a discovery was announced that may explain the origin of that view. On the barren Moroccan island of Mogador, Eleonora’s falcons have been found to imprison small birds by trapping them alive. The falcons breed on Mediterranean islands, waiting until late in the autumn to raise their young on the enormous numbers of southbound migrants that use the islands as stepping-stones for the long sea crossing. During a census of the falcons in 2014, Abdeljebbar Qninba of Mohammed V University in Rabat, Morocco came across small birds trapped in deep cavities, their flight and tail feathers removed. Crippling and imprisoning prey might be a means of dealing with the peaks and troughs of abundance, keeping fresh food nearby to feed their young during quiet periods. At the end of the season, the falcons undertake their own long journey over Africa to winter in Madagascar.
Adapted from The Long Spring pp. 118-121
