1. Observe the flight movements
Observe the unique behaviour and ‘jizz’ (character) of each species. Do they zigzag, spiral upwards or have a direct flightpath? Do they flutter or glide? How do they hold their wings and bodies when at rest?
2. Rear caterpillars at home
Easy species to rear include the peacock (above), small tortoiseshell, comma and red admiral (all of which feed on stinging nettles), and large whites (which like brassicas). Keep them in a well-ventilated cardboard box with the sides cut away and a net curtain, gauze or fine muslin glued over the top. Replenish the foodplant frequently, and watch out for mould.
3. Learn the diagnostic features
Get into the habit of scrutinising both the upper- and under-wing, focusing on key features such as wing shape, patterned wing margins and the number and arrangement of spots. Remember that males and females can differ in both coloration and behaviour – females may be more hesitant, reluctant fliers, for example. Second or third broods may appear different, too, while some species also have variant colour morphs.
4. Get counting
Don’t just watch – count. Take part in the Big Butterfly Count or carry out regular transect walks along an imaginary corridor 5m wide, noting the species you encounter. There’s also the national butterfly-monitoring scheme – visit www.ukbms.org.uk for details.
5. Time it right
Go out when activity is peaking – butterflies have distinct flight seasons. Watch the weather – a warm spring may mean adults emerge earlier, but cool or wet conditions can dampen numbers.
6. Find the foodplant
Knowing the foodplants of both adults and caterpillars will help you to predict where butterflies might occur. Some species feed on dung, rotting fruit or the honeydew excreted by aphids, while the larvae of several blue butterflies develop inside ant nests, for instance.
7. Sketch or paint
Painting or sketching butterflies, rather than simply snapping them with your macro lens or smartphone, is a great way to train your eye to observe specimens more closely. Due to butterflies’ relatively flat, two-dimensional form when viewed from above, it’s easy to record wing shape and pattern, though it can be somewhat trickier to capture the poise and vivacity for which these insects are renowned – and celebrated.
8. Use close focus
Close-focus binoculars will be a revelation. Invest in a pair that focuses down to 1–2m in order to see sun-basking, courtship, egg-laying and feeding in close detail without disturbing your subjects.
9. Visit a hotspot
Plan a few visits to butterfly hotspots. While some British species remain widespread or are strong migrants that can turn up almost anywhere, others are very local and seldom travel far, so require a special trip to be seen. Britain’s top spots are listed at www.ukbutterflies.co.uk
10. Hunt eggs
Go on a butterfly egg hunt. Begin by looking for the eggs of common species and remember that females don’t simply select the right larval foodplant – they may also deposit their eggs in a precise area, such as a stem junction or leaf underside. A magnifying glass helps, or turn your binoculars upside-down and look through the ‘wrong’ end.
Image: peacock butterfly Inachis io
Butterfly watching in Britain has gone from collecting mania to mass-participation science. Richard Jones looks at how our understanding of Lepidoptera has evolved, and asks why they fascinate so many people in the May 2015 issue of BBC Wildlife Magazine.