ANOTHER LIFE:MY OLD BINOCULARS, tin rims bare through years of bouncing on my chest, serve well enough for dragging nature near: seven collared doves on the garden ESB wire this morning. My new ones, from Nikon, are glasses for a high-tech opera box, snug in one hand and narrowing twin visions to a Cyclopean stare.
Focusing down to half a metre, they are for dragging near-nature into close-up. At one end, so to speak, from one’s armchair, the intimate inspection of a goldfinch on the rose bush outside the window, just for the colours and the twinkle of the eye. At the other, outdoors, for peering after butterflies and trundling beetles, or following a bumblebee into a foxglove’s bell.
Is this just the novel pleasure of such close company, or the urge to spy for discovery? I seem to have settled for the first. But in tracking – or trying to – the flights of the acre’s most familiar butterfly, I’m delighted to find it the subject of so much scientific interest.
The speckled wood, Pararge aegeria, is not the most glamorous of butterflies – petite and dark brown, with cream-coloured spots on its wings.
It thrives in a dappled light of woodland, which is why it has multiplied as our trees have grown. But it is also a distinctive example of compulsive territorial behaviour – an impulse well spread throughout nature, from the staged tournaments of ant colonies to battles between nations.
Three broods through the year keep the insect on the wing from April to October, fruit of the industrious sex life at the heart of its interminable skirmishes. The male speckled wood takes up its post on a leaf in the sort of sunny patch a female might fancy for laying eggs, and flies up to harass any male competitor for such a good pick-up spot. As I write, the claimant to a sun-warmed branch of golden juniper has rocketed up to whirl another rival away.
Territoriality is not exactly rare among insects. There’s a bumblebee that batters competitors for its patch of flowers, and river caddis-fly larvae that drive intruders from grazing their stretch of algae.
Even fruit flies, it seems, can defend their square of rotting compost.
Dragonflies are notorious territorialists. The big four-spotted chaser of Irish moorland, Libellula quadrimaculata, just like the speckled wood butterfly, defends areas attractive to broody females, and its combats sometimes end in damaged wings.
The speckled wood, on the other hand, exemplifies what one researcher calls “elaborate non-contact aerial interactions in which success is determined by relative persistence”. Stamina, in other words, is what counts in flying rings around the intruder – not size, shape, better wing muscles or superior acceleration (all tested for in captive experiments). Occupying and intruder butterflies circle each other closely in an ascending spiral until one – invariably the intruder – gives up and flies away. But protracted contests only occur, some studies suggest, when both butterflies “think” they are the resident. The battles can be seen drifting across a glade or road and then, as the Irish lepidopterist Jesmond Harding has noted, contestants “are oblivious to danger and can be struck by traffic or snatched by spotted flycatchers or dragonflies”.
Meanwhile, the territorial sensibilities of many Irish farmers are causing problems in mapping the scattered colonies of our most endangered and declining butterfly, the marsh fritillary, Euphydryas aurinia.
All EU member states have to designate protection sites for the species and report on its status once every six years. Needing a current survey, the National Parks and Wildlife Service sought existing records of locations gathered in by the voluntary group Butterfly Ireland. As it tells on its website (butterflyireland.com), the group was worried that its recorders might be sued for trespass or damages, or barred from future access to land, if, to protect marsh-fritillary habitats, farmers found themselves restricted by a designated special area of conservation. It sought indemnity for the recorders, or disclosure of their sites at something wider than a square kilometre, but several meetings yielded no agreement.
The National Biodiversity Data Centre (supported by the NPWS) has since launched its own butterfly-recording scheme, appealing in particular for records of the marsh fritillary colonies (butterflies.biodiversityireland.ie). While Co Donegal is still a stronghold, and Co Roscommon has many records, the species seems absent from the south and east of the country.
Now, as it happens, is the time to spot the webs full of caterpillars on the butterfly’s food plant, the devil’s bit scabious, growing in damp meadows or at bog margins. “Please,” urges the survey sheet, “make sure you have the permission of the owner before surveying a site.” And “surveyors should be aware of the potential risks of field surveying”.
Territorialism, though it doesn’t say, might be one of them.
Eye on nature
I found a bees’ nest in my garden behind a tuft of long grass next to a cherry tree. The bees are smallish with a burnt orange head and four or five thin black stripes on the body. Are they honey bees or bumblebees?
Dyan Smith, Ennis, Co Clare
It sounds like the tawny mining bee, which is solitary, each female having her own nest, but several can make adjoining nests. It is late for them to be active, but they often try for a late brood if there is pollen around.
In mid-August I saw up to 42 large thrushes, with brightly coloured spotted breasts, feeding in the early morning in the Phoenix Park. They have not been there during the summer months.
Frank Folan, Palmerstown, Dublin 20
They sound like mistle thrushes, which tend to flock during the late summer.
My wife came upon a brownish raptor holding down two crows in the middle of the road, one dead, the other stunned. A flock of crows wheeled above, making a big fuss. The raptor was slightly smaller than the crow. Could a peregrine falcon knock two crows at one go?
Peter and Stephanie Coughlan, Carrigaline, Co Cork
A peregrine could certainly knock one. Two may have been a lucky strike.
Michael Viney welcomes observations at Thallabawn, Carrowniskey PO, Westport, Co Mayo, or e-mail viney@anu.ie. Please include a postal address
