Field notebook
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Field notebook
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Permanent editions
Published facts keep their original date, evidence and correction trail. Drafts and withdrawn editions are never mixed into this index.
Tracking devices carried by common swifts showed non-breeding birds remaining in flight for most of a ten-month period, with some individuals recording no landing at all between breeding seasons. They feed, drift and apparently sleep on the wing.
Hibernation from around October to April accounts for half the calendar, and in cool or wet summers the dormouse adds bouts of daytime torpor on top. An individual may spend three-quarters of its life inactive, which is why it lives unusually long for its size.
Before swallowing a bee or wasp, a European bee-eater strikes it against a perch and then rubs the abdomen along the branch, expelling most of the venom. Only stinging insects receive this treatment; harmless prey is swallowed directly.
Slate-coloured, Oregon, pink-sided, grey-headed and white-winged juncos look like separate birds and were once named as separate species. They are now lumped as one, and the plumage groups appear to have diverged very recently.
Cuttlefish have only a single visual pigment in the retina and cannot distinguish colour the way vertebrates do. They nonetheless produce camouflage that matches coloured backgrounds convincingly, both to human observers and to the fish that hunt them.
The long-eared hedgehog's usual answer to a threat is speed. It sprints, and its oversized ears radiate heat in arid country where a curled, immobile animal would overheat as well as be caught.
Unlike its black relative, the eastern green mamba is strongly arboreal. It hunts, rests, mates and sheds among branches, and its brilliant green body against sunlit leaves makes it far harder to see than the colour suggests.
Generations of Arctic foxes concentrate nutrients at a den through urine, faeces and prey remains. On nutrient-poor tundra the result is a visible green patch of much denser vegetation, detectable from the air.
Through summer a pika harvests plants, carries them to a sheltered rock cavity and spreads them to dry, building a haypile of several kilograms. It eats from that store all winter beneath the snow, since unlike marmots it does not hibernate.
In 2009 the Diasan Shinsho-maru rolled over off Chiba while its crew tried to haul a net filled with Nomura's jellyfish. The three crew were rescued. Each animal can weigh as much as an adult person, and a bloom fills a net with hundreds of them.
Bearded capuchins in Brazil crack palm nuts with stone hammers on stone anvils. Excavation beneath the anvils has recovered layers of used hammer stones, showing the same behaviour has continued at the same sites for roughly three thousand years.
Eastern bluebirds cannot excavate their own cavities, so they compete for holes made by others. Twentieth-century declines tracked the loss of dead trees and wooden fence posts, and a volunteer network of nest boxes along set routes reversed the trend.
The maze pattern is not decoration and not a single animal's folding. Each winding valley is a meandering series of polyps that never finished dividing, leaving their mouths joined end to end along the floor of the groove.
The stalk buried in the mud is not a root. It is a single enormously enlarged polyp, the primary axial polyp, and every feeding polyp on the branches above is a secondary polyp budded from it and permanently attached.
So few Pacific footballfish have ever washed up on Californian beaches that each new one is logged as a notable event, with fewer than about thirty specimens recorded worldwide since the species was described.
Kept warm all year, a Hermann's tortoise tends not to breed. The species brumates through the Mediterranean winter, and that cold dormant period appears to be part of what sets up the following spring's reproductive cycle.
Remove the dominant male from a group and a female begins behaving as a male within minutes. Over the following days her gonads convert to testes, and gene expression across the tissue is substantially reprogrammed.
Dense zebra mussel colonies filter so much plankton that water clarity increased measurably after their arrival. The clarity is not recovery: it reflects energy stripped from open water and diverted to the lake bottom.
Pseudis paradoxa larvae reach around 25 centimetres, while the adult frog measures roughly seven. The animal shrinks substantially during metamorphosis, reversing the usual direction of amphibian growth.
Dentalium shells, strung in standard lengths, functioned as a widely accepted medium of exchange and wealth store among Indigenous peoples of the Pacific Northwest and interior, long before European trade goods arrived.
Female wolverines dig natal dens in deep snow that persists into May, using tunnels and structure beneath the surface to shelter kits. The link between denning and late-lying snowpack is strong enough to predict where the species occurs.
The pied avocet had been lost as a British breeding bird for about a century. Coastal marshes deliberately flooded as an invasion defence during the Second World War created exactly the shallow brackish lagoons it needs, and the species returned in 1947.
Losing lungs sounds like a handicap, yet the lungless family Plethodontidae accounts for roughly two-thirds of all salamander species. Breathing through the skin freed the mouth and throat for a projectile tongue instead.
Most canids carry 42 teeth. The bat-eared fox has up to 50, with additional molars and a jaw muscle arrangement built for rapid chewing, because roughly four-fifths of its diet is insects, dominated by harvester termites.