Wildlife Watching - April

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Mammals

Mid-March is the peak time for fox births, so April is the month during which most litters will emerge from the earth and get their first taste of the outside world. Certainly many rescue centres start to see their first fox cubs of the year now. By the time the cubs appear above ground they’re five or six weeks old and are very playful – brilliant to watch if you’re fortunate enough to have an earth nearby. This is also a good month to see adult foxes out and about as they hunt around the clock to provide food for their ever-hungry litter. As we’ve passed the spring equinox, the hours of darkness in which foxes can hunt are diminishing, so activity is much more likely to spill over into daylight, even in rural locations where foxes tend to be more nocturnal.

A wood mouse (Apodemus sylvaticus). - Credit: Hanna Knutsson

Badgers are becoming increasingly active now; the sow needs to remain well fed so she can provide milk for her growing cubs, particularly as most youngsters won’t appear above ground to start foraging for themselves until next month. Brown hares are also very active and it’s a good opportunity to see them chasing and boxing before the vegetation grows taller and obscures their movements. Water voles are quite busy, and April marks the start of the water shrew breeding season, making a walk along your local river a worthwhile activity. April is also a good month to go small mammal spotting, with wood mice and bank voles busy among the leaf litter and log piles. Bank voles will start breeding towards the end of the month, the season running until about September, while many wood mice have already produced their first litter of pups by now, their breeding season having started back in February.

Loathed by many gardeners but endeared to generations of children that have grown up with Kenneth Grahame’s 1908 book, The Wind in the Willows, there can be few other British animals that are as well-known but as seldom seen as the mole. Few people have ever seen a live mole, and yet large spade-like front paws, tiny eyes and soft black velvety fur are all characteristics that we immediately associate with this mammal, thanks, in part, to Arthur Rackman’s true-to-life illustrations of Mole in Grahame’s novel. Molehills tend to start appearing in greater numbers during April, much to the fury of gardeners.

Mole hills appearing in lawns and borders is a good sign that things are starting to warm up after winter, as the moles move into shallower soil and begin excavating their tunnel networks. - Credit: Marc Baldwin

In most cases, molehills are relatively small conical spoil heaps, not greater than about 20cm (8in.) high. In some instances, however, a larger heap may be created, covering a nest chamber filled with woven dried grass and other vegetation and housing several caches of earthworms collected during times of plenty. In extreme cases, such large mounds may contain up to 750kg (1,600 lbs) of soil and stand 100cm (just over 3ft) tall. These “fortresses” represent a significant investment for a mole and it has long been a puzzling construction for such a small mammal. Early naturalists believed the fortress offered escape for the mole if the soil flooded as they’re often, although not exclusively, built in shallow soils which may be more prone to flooding than deeper ones. A fascinating experiment by Martyn Gorman and David Stone, however, suggested a different reason. Gorman and Stone inserted a thermostatically-controlled heating element into a dead mole and placed it into a nest box to assess what impact covering it in soil had on heat loss in freezing conditions. The biologists found that, when they covered the mole with a fortress of soil about 150cm wide and 100 cm deep (i.e. 5ft by 3ft), it reduced the heat loss by 30%. So, the fortress seems to play an important role in keeping the mole warm as well as providing convenient storage for its earthworm larders.

The reason for the sudden increase in molehills at this time of year is twofold. Firstly, as the weather warms up, earthworms move up into shallower soil to feed and breed, and the moles follow them. Secondly, it is the mole breeding season. Depending on the weather, the breeding season spans late February to early June in the UK (starting earlier in southern England than in Scotland, presumably in response to spring temperatures) and the female mole is receptive to mating for only three or four days during each cycle. Gestation lasts for about four weeks with most pups born during April/May in southern England and June/July in Scotland; in southern England, a second mating may occur during the summer.

Many of our red, fallow and sika deer will cast their antlers now, and some of the larger bucks and stags have already started. Despite some bleeding, the casting process is painless for the deer, and they often seem a bit surprised by the sudden loss of head weight. Antlers are usually cast within an hour or so of each other but some may drop a day or more apart, leaving the stag wandering around with only one antler attached. The newly-cast antler will be left where it falls and the wounds heal over quickly. Growth of the new antler will start immediately and by the end of the month you’ll see some of the larger stags with small velvety lumps on their heads. You may be fortunate enough to come across an antler while out walking and, in rare cases, even a pair together. Bear in mind, however, that the cast antler is bone and offers a valuable source of minerals to the deer as it re-grows it new antlers. Consequently, deer will often eat cast antlers, and you’d be helping them out if you didn’t collect too many.

Birds

April can often be a bit of a slow month for birders, with many of the winter residents having left and the summer visitors having yet to arrive. It’s not uncommon to find a pair of great grey shrikes hanging around on southern heathlands, and cuckoos can turn up at any time. There’s a cacophony of birdsong now which continues late into the evening thanks to the longer days, and this is starting to include chiffchaffs. These small olive-coloured warblers are resident in some of south of England and Wales, but many more arrive from the continent during March, migrating up the country during the spring and summer. Cetti’s warblers, woodlarks, tree pipits and meadow pipits also start making an appearance this month.

A pair of kingfishers mating. - Credit: Jeff Harrison

Great crested grebes will be looking for nest sites and there are still plenty of opportunities to watch their entrancing courtship dances (see: February). Also by the water, mid-April marks the first kingfisher clutches being laid, and they will have several more broods during the summer. Kingfishers are more akin to sand martins in their nesting behaviour than other birds; rather than building nests in trees or among ground vegetation, they excavate a chamber in a riverbank. The courtship process begins early in the season, with some males beginning the wooing in February. At first, the male may behave aggressively towards any female present, but this soon subsides. Curiously, the courtship display – which consists of the male standing in a stretched upright position, with wings draped forward and head just above horizontal – is quite similar to the threat display, although it’s typically accompanied by soft whistling. During the next few days the frequency of courtship displays declines as the pair-bond becomes better established. The male will also chase his prospective mate while calling continually and will periodically present her with fish to show off his fishing skills, spotlighting how suitable a provider he would be for her young.

Ospreys will be appearing in our estuaries in the next couple of weeks, while swallows, swifts and martins will start screeching across the skies. Other feathered species to look out for in April include redstarts, hawfinch, song thrushes, starlings, lapwings, herons, firecrest, Dartford warblers, skylarks, yellowhammers and egrets. Many birds of prey will start breeding now, including goshawks who may already be on eggs. Tawny owls are the earliest of our breeding owls and many will be on eggs now; watch out for the fluffy light grey owlets sitting on branches near the nest during late April or early May.

Reptiles & amphibians

April is a good month to go out reptile spotting. Grass snakes are often found in woodland and farmland habitats, typically close to water; they are accomplished swimmers and frequently take frogs and fish. Adders can crop up anywhere but tend to be found basking in sunny woodland clearings and on heathland, the latter a preferred habitat for most reptiles.

Grass snakes have a catholic diet and will readily take to the water to hunt frogs, newts and fish. - Credit: Ian (CC BY-NC 2.0)

I find that warm, dry but overcast days with light winds are particularly good for reptile photography. Because it takes them longer to warm up, they’re less likely to immediately scarper from their basking spot, allowing time for a couple of photos. If you do startle a basking adder or grass snake, sit and wait – they often have favoured basking spots and may return to continue basking after 15-20 minutes. It is also worth checking around compost heaps and sunny corners of gardens and allotments for slowworms; these legless lizards are common garden residents.

I should take this opportunity to reiterate that, when watching or photographing animals, their well-being must come first. If it looks like you’re disturbing the animal, move away slowly and leave them in peace. I always use a long lens (400mm or longer) so I can maintain a respectful distance.

Amphibian-wise, there are still a few spawning frogs to be found, but most of the activity seems to have died down now. Indeed, depending on how mild the end of winter was, some ponds will be teeming with very active tadpoles this month. Newts are still breeding, and it’s worth looking closely in the shallow end of your local pond for the tail-flicking display that the males use to woo females. Once mated the female lays eggs, which she wraps in the leaves of water weed. If you check the submerged vegetation around the edge of the pond, you’ll likely find some with leaves folded over; each folded leaf will hide a single egg.

Invertebrates

As the weather warms up, butterflies are becoming an increasingly common sight, with small tortoiseshell, peacock, brimstone and comma likely to be encountered now. Other species to watch out for this month include orange-tip, holly blue, green hairstreak, green-veined white, speckled wood and pearl-bordered fritillary. There are also a lot of wolf spiders to be found and, as spring progresses, keep an eye out for females carrying pale blue or cream egg sacs. The ungainly oil beetle, with its big lustrous black body, can be found on wildflower-rich heaths, grasslands, moorlands and coasts during April – if you find one, please report it. Other species of interest this month include the black dangly-legged St Mark’s fly, which forms large swarms in April, and the bee fly, a fascinating fly that has evolved to look like a bee so it can get close enough to the nests of solitary bees and wasps to flick eggs into the entrance. Once hatched, its grubs head into the nest to feed on the bee/wasp larvae.

The bloody-nosed beetle (Timarcha tenebricosa) gets its name from the bright red fluid exuded from its mouth when alarmed. When threatened, the beetles rupture some tissues in their mouth, causing them to exude red/orange haemolymph, distracting the would-be predator while the beetle makes its escape. - Credit: Giles Watson (CC BY-SA 2.0)

The UK is home to about 4,000 species of beetle and April is a good month for turning over logs to look for them. Beetles out and about this month include various species of ladybird, bloody-nosed beetles, minotaur beetles and green tiger beetles.

Plants & fungi

Blossom is a sign of spring (even though it often arrives during the late winter) and there is an increasing amount on display now. Spring storms are sometimes a problem for blossom-bearing species, because the flowers and petals can quickly be stripped by strong winds. We saw this with the unusually powerful “Storm Katie” that swept over the UK in March 2016. Blossom is energetically-expensive for the tree to produce and, if it is lost before the tree is pollinated, cannot be replaced. The result is that there is likely to be less fruit come the summer and autumn.

Verges and banks will soon be alive with colour provided by campion, violets, forget-me-not and daffodils. If you’re fortunate enough to live near some chalk grassland you may find some striking purple pasque flowers, which are in bloom during April. The so-called “high-rise primrose”, otherwise known as cowslips, with their fabulous honey scent, also bloom in open pasture and download now, and bluebells are starting to make their presence known in our woodlands.  Common dog violet and the sweet-smelling magnolia flowers are also in bloom in April, and wild garlic, which perfumes the air with its distinctive heady aroma on warm days. The leaves of wild garlic are edible, but be sure of your identification because similar-looking plants (e.g. Lily of the Valley, meadow saffron, arum lily, etc.) are poisonous.

Blossom is energetically expensive for trees to produce and cannot be replaced. Consequently, spring storms that strip it off can have serious implications for the fruit harvest later in the year. - Credit: Marc Baldwin

There isn’t much in the way of fungi about this month, although St George’s mushroom fruits now, producing large, creamy-white caps up to about 15cm (6 in.) in diameter on old grassland and in birch woodland.

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