Seasons: Spring

March madness

Hares are usually nocturnal and shy, but their behaviour changes in the spring (usually in March) when they can be seen chasing one another around fields and meadows in broad daylight, and apparently attacking or “boxing” each other with their front paws. This behaviour was once believed to represent contests between males but it is now clear that these boxing matches are usually between males and females.

A female will fight off her numerous suitors if she is not ready to mate. These fights can be quite viscous and there is some evidence that this behaviour is aimed at testing the male's strength before deciding whether to proceed onto the next step of courtship. When a doe is ready to mate, she runs and starts a chase that will test the fitness of the following males. When only the most dominant male remains, the female will stop and allow copulation. Hares lay up to three litters a year between February and October. There have been significant declines in hare population in England and, despite this, they are still hunted in winter.

Chemical attraction

Butterflies emerge from hibernation some time in April when the weather becomes warmer. Their first task is to find food and then to breed. The mate-locating and courtship displays of butterflies varies among species but generally males seek out females for copulation. Recognition of species takes place using vision and chemical cues in the form of pheromones. Once a conspecific female is located, the male initiates courtship, which may involve a complex display of visual, tactile or olfactory stimuli before copulation can take place.

Pheromones are produced from glandular structures located at the base of specialized scales on the wings called androconia and are wafted across the female’s antennae during courtship. Contact pheromones are also used in some species. In the grayling, the male clasps the female’s antennae between his wings to bring them into direct contact with his androconial scales. In some species, (for example, the wood white) the male repeatedly flicks out his proboscis, whipping the female on the underside of her wings.

Males sometimes pursue other males resulting in aerial dogfights in which the ownership for good vantage points to intercept passing females is contested. These territorial battles can last for several minutes, after which one male is ousted from the vicinity.

Strutting their stuff

The black grouse is the fastest declining bird in the UK. It is well-known for its breeding display, which has been extensively studied and is known as a lek: Males gather on an open area of ground where they strut, fan their tails, spread their wings and inflate wattles around their eyes while emitting a highly distinctive mating call. The sole purpose of this display is to attract a female.

Although males lek all year round, females only attend the lek in late March to mid-May when male activity reaches a peak. Females are very selective about the male they mate with, making their choice only after watching the displays of several males. There is also evidence that males that display from the centre of the lek are preferred by females. This results in intense competition among males to occupy central positions. Hens lay 6-10 eggs from late April to early June.

Spring migration

In spring toads emerge from their overwintering sites and make their way to their natal ponds. The spring migration can consist of hundreds of individuals and in many places in Britain, toad patrols are set up to help them cross busy roads to reach the pond. Spring migration is a consequence of hormonal changes. Once they reach water the males actively search for females and on finding one, clasp her in a hold known as amplexus. The mating system is known as scramble competition since males will attempt to clasp any moving object, including other males. Sometimes this results in the formation of a mating ball with several males trying to clasp a single female at the same time. Females can often drown at the centre of these balls.

Once a male has clasped a female and seen off other males, the pair remain in amplexus for several hours until the females extrudes her eggs and the male deposits his sperm over them. Fertilisation is therefore external and eggs are laid in long strings. Breeding can start as early as February depending on temperature – toads rarely spawn at temperatures below 6 degrees Celsius. Once they have spawned, toads leave the pond and return to their summer habitat to forage and feed.

Writhing mass

The grass snake is Britain’s largest terrestrial reptile. They emerge from hibernation in the spring (April). Males seek out females for mating and several males can be simultaneously attracted to a single female. The consequence is the formation of a mating ball where up to eight males and one or two females form a writhing mass. The male that successfully mates with the female is the one that manages to insert his hemipene into the female’s cloaca thereby excluding other males. Eggs are laid in June and July and hatchlings emerge in autumn.

Reproductive success

Several mating combinations exist within dunnock populations, including monogamy, polyandry (two or three males with one female), polygyny(one male with two females), and polygynandry (two or three males with two to four females). Male reproductive success is greatest in males that mate with several females (polygynous) but low in polyandrous relationships. In contrast, for females, reproductive success increases in cooperative polyandrous relationships but is low when several females mate with one male (polygynous). As a result, there is sexual conflict between males and females with each sex attempting to maximise reproductive success at the expense of the other.

Courtship

In 1914 the zoologist Sir Julian Huxley published a paper called ‘The courtship habits of the Great Crested Grebe’ and ever since, grebe courtship has fascinated people interested in animal behaviour. The courtship display involves a number of stages, starting with a pair meeting on the water, shaking their heads and dipping their necks. This behaviour continues for several minutes and culminates in a 'weed dance' where both birds dive underwater and collect weed in their beaks before rushing towards each other, low above the water's surface, then rising upright to meet face to face.

Carpet of blue

Bluebells which have overwintered as bulbs, begin to flower. In spring the leaves emerge from the bulb and the characteristic scented blue flowers develop. When growing en masse in woodlands they create a dazzling display of brilliant blue.

Blooming spring

The primrose is a common sight in hedgerows, woods and fields throughout April and May. It reproduces from seeds which are dispersed by ants. A single primrose plant may live for 15-25 years.

Behold the queen

One of the most significant signs of spring is the emergence of large bumblebee queens from hibernation. Queens are seen flying around searching for nesting sites. Once they have located a site they collect pollen which is moulded into a mass and forms the base of a cell made of wax in which the queen lays her eggs. The queen then constructs a thimble-like wax honeypot, which she stocks with nectar. Once they hatch, the larvae feed on the nectar and pollen. The queen remains in the nest after larvae hatch and workers take on the task of collecting pollen and nectar. Bumblebees seen in summer are usually female workers or males.

Important pollinators

Along with bees and hover flies are other important pollinators - butterflies. One of the most common species seen in Britain is the Meadow Brown and one of the first to emerge in spring is the Brimstone butterfly. The Red Admiral is a migratory butterfly that arrives in England from the continent in spring. Many now overwinter in the south of England and those that do, emerge from hibernation in February and March. They lay their eggs on the tips of nettles, which the emerging caterpillars eat. Adults feed on nectar.

Springtime mimics

Hover flies are a common sight in spring. The adults of many species feed mainly on nectar and pollen and are therefore, along with bees, important pollinators. Hover flies are good mimics of bees and wasps and are often mistaken for them.

Mates for life

Ospreys arrive back in the UK from Africa in early spring (March–April). They usually mate for life (they are monogamous) and use the same nest year after year. Therefore, although the male and female are apart during the overwintering season in Africa, they pair up again at the nest when they arrive back home. The female lays 2-4 eggs, which hatch after about five weeks of incubation. Both parents incubate eggs and care for chicks.

Social monogamy

In early April, swallows return to the UK from Africa. They are socially monogamous but genetic fingerprinting has shown that both males and females often seek extrapair copulations. They return to the same nest year after year and so, like ospreys, meet up at the nest after arriving back in the UK. Females lay 2-7 eggs. Males help feed the young and in some species they help incubate the eggs. In the European subspecies most if not all the incubation is carried out by the female. Recently, an incidence of infanticide has been reported in a nest in England.

Parent's favourite

Both parents care for the young and take turns carrying them on their backs and bringing them food. In time, each parent develops a preference for particular young resulting in the adults dividing the brood in order to care exclusively for their favourites. Parents feed feathers to the offspring which line the stomach and aid in the ability of grebes to eat bony fish.

Mother's milk

Deer are the largest land mammals in Britain. Females give birth in late spring (after mating in autumn) and take care of young without the help of males. Males mate with several females. The young feed on their mother’s milk for about eight months after which they become independent.

Cooperative

Badgers live in social groups and have a polygynandrous mating system with both males and females having more than one partner. There is some evidence of cooperative breeding in badgers: breeding females often spend time with cubs of other females and non-breeding males and females babysit cubs. There is little evidence that breeding males care for young.

Love them and leave them

Red squirrels mate twice a year: winter mating (December-March), which leads to young being born in the spring (March–May) and spring mating, which leads to young being born in the summer (July-September). Pairs are formed each spring and separate after mating. The male takes no part in caring for young.

Litters consisting of 3-4 young are born, following a gestation period of 36-42 days. The young are called kittens and are born with their eyes closed, without teeth or hair. They are suckled by the female for 50-70 days, and weaned at 10 weeks when they are ready to leave the drey. They are generally independent by 12-16 weeks.

Den-bound

In the spring, Red fox females give birth to 4-5 cubs in a den. The female rarely leaves the den after giving birth and the male brings food to her. The cubs are totally dependent on their mother for milk. After about a month the cubs start emerging from the den and begin eating solid food, which is supplied by both the male and female. By the end of summer, the family begin to disperse.

Role reversal

There are two species of seahorse found in the south of the UK. The breeding season starts in May but is dependent to a large extent on water temperature. Seahorses mate for life.

Nearly all seahorses are monogamous (one male mates with one female). Seahorses are sex-role reversed meaning that the male cares for the young. After a prolonged courtship, the female deposits her eggs into the male’s brood pouch located on his ventral, or front-facing, side. The male fertilises the eggs internally and carries them in his pouch until they hatch. Fully formed, miniature seahorses are released into the water. Worldwide, seahorses are threatened by habitat destruction and overfishing (they are often used in Chinese medicine).