Three small butterflies

Lawns are not very interesting. Green, freshly mown grass may be good for walking on, for playing sport on, and for admiring from afar if orderliness is your kind of thing, but it isn't so useful for creatures. Short, neat stumps of grass aren't great for hiding amongst and don't provide much to munch on, and hence if a field is so manicured that it could be mistaken for Astroturf, it is unlikely to have much living in it. Let the grass grow just a bit longer however, so that the ends tickle your calves as you walk through it, and as if by magic the previously-barren spot will be teeming with life.

All manner of creepy crawlies like to hang out in long grass, from tiny ants and flies to bumblebees and dragonflies. Most colourful, however, have to be the butterflies, which flutter skittishly from perch to perch in search of tasty nectar. Larger varieties such as the Peacock and Red Admiral are easily recognised due to their distinct patterns, but just as attractive are some of the less well-known smaller species. I managed to spot three of the latter recently.

This little fellow is a Brown Argus Butterfly. Confusingly, it is a variety of blue butterfly, despite it not being in the slightest bit blue-coloured (the undersides however are similar). They are most commonly found in the south and east of the UK, preferring to spend their time in chalk and limestone grassland. With a wingspan of only about 25 mm they are about half the size of a Red Admiral and so can be tricky to spot in dense vegetation. If you do manage to clap eyes on one however, you won't have to worry too much about losing it for these are truly lazy butterflies. They rarely travel more than 200 m from the site where they emerged, and like nothing better than to lie around soaking up the heat of the sun. Interestingly, their caterpillars are tended to by ants: the ants provide protection in exchange for a honey-like secretion from the caterpillars’ 'Newcomer’s' glands.

This is another butterfly from the same family, but this time at least the males are actually blue! Such Common Blue butterflies are, as the name suggests, regularly seen all over the UK. They are not fussy about their habitat, and will happily live in gardens, on verges, or even on sand dunes. Similarly, they will contentedly guzzle nectar from all kinds of sources, with thistles and clover is being just two examples of the many plants they feed on. During the day they flap around casually from flower to flower, then at night they become quite sociable, and it is often possible to find a whole group roosting on the same grass stem.

This final specimen is the ominously-named Gatekeeper butterfly. There is however nothing remotely unsettling about it, it is simply a very small (20 mm or so) creature that likes to frequent scrubby grassland. The males tend to pick a shrub they like the look of and from there establish a little territory. The females find a mate and then set off to lay their eggs, of which there may be a couple of hundred. Unlike other butterflies, which tend to get through several generations each year, Gatekeepers only go through one cycle, which peaks at the beginning of August. This time of year is in fact when many butterfly populations peak, meaning that the countryside should be swarming with them. Go out and find some!

The Walnut Orb-Weaver Spider

I found this spider crawling around on the side of a shed last summer. With its dark, leathery, flattened body and disconcertingly slow movement, it seemed rather, well, sinister. It certainly appeared much meaner than most of the spiders to be found in the garden: a sneaky, dangerous-looking creature with something of the night about it. Concerned that it might be capable of a nasty bite, I left it well alone.

In fact, this little beastie is a perfectly ordinary, harmless garden spider. Despite being extremely common it is rarely seen as it is mostly active at night. During the day it squeezes its thin body into crevices, often under bark, hidden well out of sight of any predators. Then in the evening it emerges, cautiously, and spins its flat, circular web. Once it has finished this construction it will move to the web’s centre and stay there perfectly still, waiting for unwary flying insects to get trapped.

If the spider feels spooked during the night it will return to hide in its crevice, slowly following a guideline of silk. Before the sun rises it completely dismantles its web, leaving no trace that it was ever there. Given that the webs can reach 70 cm in diameter, this daily cycle of building and demolition seems like an extraordinary waste of effort. Maybe all this work just fills the time, or maybe the webs are actually a bit naff and so wouldn't last more than a night anyway.

If you spot one of these spiders it's likely to be a female. These are bigger, at up to 15 mm long, and are active all year. Males on the other hand only ever grow to 9 mm and are only out and about during the summer. Interestingly, if you pick up a male it may bite you, although however hard it chomps down it won't do you any real harm. The Walnut Orb-Weaver would seem therefore not to be the villain it appears. It does 'live in the shadows' as its Latin name Nuctenea umbractica implies, but this is simply because it is too cowardly to come out during the day.

Hermit crabs

Hermit crabs are a common sight by the seaside, most often spied crawling around in rock pools. Adults vary in size from around 15 to 150 millimetres. Their most prominent features are their shells, and yet these are not really part of the crab at all. Most crabs have a hard carapace that they produce themselves, but hermit crabs have soft, easily-damaged bodies and would quickly be killed without further protection. Because of this they search out the empty shells of gastropods such as whelks and periwinkles. As they grow they have to find bigger shells that can accommodate their increased body size. There is often much competition for the best shells, but once a crab has successfully obtained one it will insert its asymmetrically twisted abdomen far inside until only the front two pairs of legs remain out in the open.

Technically the crabs have five pairs of legs, but the back two of these are too small and puny to be much use for anything other than holding on to the shell, and so remain tucked away inside. The second and third sets are larger and stronger and so are used for walking, but even these are dwarfed by the first set. The front right leg has a large claw that is used for holding food and for fighting, and the smaller claw on the front left leg is used to help with eating.

Hermit crabs aren't fussy about what they eat; if they can catch it they'll have it. Any animal and vegetable matter scavenged from the seafloor will do. The crabs often have a symbiotic relationship with other creatures such as sea anemones which come and live on their shells. The crabs get camouflage and protection and in return the anemones get to eat any leftover food. Sometimes this relationship becomes so established that the anemone will 'move house' along with the crab when it changes shells.

Male hermit crabs can be quite aggressive when the time comes to mate, and will grab hold of female crabs, fighting off any competing suitors with their large right claws. Male reproductive organs are located behind their rearmost legs whereas those of the female are on the third pair. On the left-hand side of the female abdomen are structures known as pleopods which are used to carry the fertilised eggs. The baby hermit crabs do a fair amount of their development whilst tucked away here inside the eggs. When they eventually hatch and venture out into the sea they are tiny, shrimp-like creatures in desperate need of a shell.

This hermit crab lives in a tank at the Anglesey Sea Zoo, a small aquarium that only has native sea creatures on display. It is well worth a visit, with its lobster breeding programme being a particular highlight. The zoo is also a good reminder of what a great range of sea life we have in the UK, and reinforces the fact that creatures don't have to be exotic to be interesting. Great satisfaction can be derived from learning about the animals 'indoors' and then going and finding the wild versions just outside.

Anglesey Sea Zoo

Fox eats birdseed: the proof

Bullfinches

Bullfinches are quite secretive birds that are rarely seen; once spotted, however, they are unmistakable. Despite being only 15 cm or so in length, fairly standard for a finch, they look considerably larger due to their stocky, bullish shape. Adult males have a dark black cap, grey backs, black tails, white rump and, most strikingly, a bright reddish pink breast. In adult females the breast is a duller more plum-like colour which is less eye-catching but equally attractive.

Bullfinches can be found all over the UK, although they are most concentrated in the south east. They spend most of their time well-hidden in dense undergrowth in woodlands, but will sometimes venture into gardens, especially those which are large and contain plenty of shrubs. They are birds that like company, and will normally be found in a pair, or in a family group in the colder months. Their diet consists mainly of buds, berries and seeds, particularly those from the Ash tree. Unfortunately their penchant for the buds of fruit trees can make them hugely unpopular with orchard owners, who used to trap and kill hundreds of the birds. And on-form bullfinch can apparently destroy thirty buds per minute; it is unlikely to even eat all of these.

Bullfinches are not ones for flying great distances and rarely travel over 100 km in the UK. Their cousins in northern Europe are more adventurous, and often make migrations in search of food, but those here prefer to stay put, making use of garden seed feeders in times of scarcity. To breed, female bullfinches find concealed spots in bushes or small trees and build small, untidy nests from twigs, moss and fine roots. Into these they lay four to six greenish blue eggs which soon hatch into fledgelings that are looked after by both parents.

A female bullfinch seeing off the approach from a greenfinch on a snowy day in the garden.

Despite their reputation for shyness and secrecy, the family of bullfinches that have taken up residence in our garden this year are rather ballsy characters. Whereas most birds fly out to the feeder, hover there long enough to take a quick peck and then scarper, the bullfinches will quite happily sit on the feeder’s edge for extended periods of time, shooing off any other birds who try to get close. They are not at all easily spooked and give off a definite air of being 'in charge'... at least until something really big like a buzzard turns up!

Fieldfares

Fieldfares are the most colourful members of the thrush family. About the size of a blackbird at around 25 cm long, they are distinguished from other thrushes by their blue-grey heads, black tails and reddish breasts. They are common in northern Europe and Asia all year round but only visit the UK for the winter. Most fieldfares seen in Britain have made the substantial trek over from Scandinavia, arriving exhausted at our shores from October onwards. Once here they are most often head for farmer's fields and parkland, where they form large flocks with similar birds such as redwings. If food is scarce they will occasionally venture individually into gardens, taking advantage of grain and seed left out for them by humans, but by far the best place to see them is the open countryside.

Their diet mostly comprises worms and insects, which they peck their way through soft earth to find. If the ground freezes and this activity becomes impossible then they will feed instead on fruit and berries, with hawthorn bushes being a particular favourite. In the event that conditions become particularly harsh they may even give up on the UK and migrate further south into the continent. Fieldfares are rather nomadic and have no real loyalty concerning where they head to. They will migrate to a different place each year, if they bother to migrate at all; many are quite content not to fly all the way over the North Sea and hence remain all year in Scandinavia. Those who do come over here will return home by May at the latest in order to breed. They build their tidy nests in trees, often in groups, and lay five to six speckled blue eggs.

This particular fieldfare has spent all day in our garden, putting up with the odd bit of bullying from blackbirds in order to feast on some apples that we laid out this morning. He (or she, the sexes are very similar in appearance) has grown in confidence throughout the day and now seems quite content in what for him is not a particularly natural environment. In fact, as I write this he has grown sufficiently cocky that it is him chasing other birds away rather than the other way around! The snow has been lying thickly on the ground for over a week now, and so he has ventured away from his normal haunts in search of an alternative food supply, which we are more than happy to provide him with. As long as he leaves some for everyone else...

Birdseed: a universal foodstuff?

Most creatures are quite specialised in what they will eat, carving out a niche based upon a particular foodstuff in a particular habitat, becoming perfectly adapted via the evolutionary process. However, if the evidence from our garden is anything to go by, many animals will quite happily cast aside millennia of specialisation in order to gorge upon Haith’s Original Wildbird Food. As the name would suggest, this feast of seeds and grains has been concocted with wild birds in mind; small, busy birds like blue tits and robins and chaffinches. It was not, it is safe to say, designed for cats, deer and foxes.

Haith's Wildbird Food: manna from heaven?

Why then do these three in particular go crazy for it? Deer at least are herbivores, and so seed isn't too much of a stretch from their usual diet of leaves, twigs, fungi and the like; foxes are omnivorous, although most of their diet is made up of invertebrates; but domestic cats are carnivores through and through. Their bodies just aren't designed to deal with nuts and seeds. What is it then about birdseed that is just so good?

One possibility is that the cats are simply pretending to eat the seed, lurking around the vicinity of the feeder in the hopes of ensnaring an unwary bird. Or it could be that the seed, having often been kept in garages or warehouses where small rodents abound, smells irresistibly of mice. However, a lot of the time the cats do seem to be genuinely eating the seed, fully concentrated on gobbling it up and as such blissfully aware of what is going on around them. And I have heard tell that dogs will lap the stuff up also.

One factor that may well play a role is the huge amount of energy packed into the tiny seeds. For example, sunflower seeds provide a whopping 6.5 kilocalories per gram (compared to 5.0 kcal / g in custard creams and a measly 0.3 kcal / g in carrots). When it's cold outside and food is scarce, this is not to be sniffed at, providing one has a digestive system that allows it to be absorbed. The ruminant stomachs of deer will certainly be fine, and that of the fox will have a good bash, but cats? They simply don't have the right kind of teeth to even get started on the process.

Perhaps cats are simply not very bright. This is certainly the case for one of ours, and indeed it is she who seems to chomp down the birdseed most voraciously. Or perhaps they are simply economically savvy: after all, Haith’s sunflower seeds for birds cost around £2 per kilogram whereas those designed for human use from Julian Graves come to an astonishing £7 per kilogram. It would thus seem that people should start munching on the birdseed too!