Nightingales in November (35 page)

Another chick pushing its ‘parents' to the limits by mid-June will be the Cuckoo. By now much larger than its foster parents, this huge size difference doesn't seem to prevent the chick's industrious hosts from realising anything is wrong as they continue to stuff the youngster with food from dawn to dusk. Quite often in order to ensure the food reaches its required destination, the host adults may even need to stand on the Cuckoo chick's back in order to reach its gape, and the nests of Reed Warblers and Meadow Pipits soon look manifestly unfit for purpose as the chick grows out of house and adopted home. Feathering up quickly, the Cuckoo
chick will by now be quickly developing the characteristic white feathers on the back of its head and on spotting its ‘parents' approaching with food, the distinctive hissing call can be heard from quite some distance. Upon arrival of the food, the bird seals the deal with a demonstrative begging gape and quivering of wings.

Despite eating enough for four or five, the young Cuckoo will actually take longer to fledge than the chicks of most of the host species it parasitises. Certainly in Britain, Reed Warbler and Meadow Pipit chicks will leave the nest after around 12 to 14 days and be dependent on their parents for only a further 12 days afterwards. This contrasts with the Cuckoo needing anywhere between 17 and 20 days in the nest, and still reliant on its hosts for almost as long again, before its departure finally relieves the burden from its beleaguered foster parents. After leaving the nest, the young Cuckoo will usually seek the safety of nearby bushes, where it will then continue to noisily beg for food. Looking rather like an adult Cuckoo at this stage, the fledgling will usually tend to be a touch more rufous in colour and with heavy chestnut barring on its upperparts. It also pays for the greedy youngster at this stage to remain initially largely hidden and perched in one place, as its silhouette in flight will frequently illicit aggressive responses from many local birds and even leading to it being mobbed by its own foster parents! Often extending its shameless begging repertoire to any passing bird, it seems the parental urge of other species does occasionally extend to ensuring this bare-faced cheat will continue to be fed by all and sundry until full independence finally sees it foraging for its own food.

The extended adolescence of Tawny Owls means any fledged young by mid-June will not only still be hanging around their parents' territory, but also utterly reliant on any food brought
to them for some time yet. Tawny Owl expert Dave Culley has followed his neighbourhood pair through a number of breeding seasons. Breeding in a small yet wooded suburban location in Cheshire, Dave has found that in April the owls' diet consists of around 40 to 50% birds. But by June as much as 90% of all the prey caught and brought to the youngsters will be feathered. With the constant pressure to find sufficient food to feed their young, the adults at this time of year will capitalise on the easy prey of recently fledged birds, even hunting during the day when the opportunity arises. With numerous cameras set up throughout his owls' territory, Dave has even managed to film one of the Tawny parents snatching a female blackbird incubating a clutch right off her nest!

Like their Tawny counterparts, young fledged Peregrines will also be some way off being able to feed themselves by mid-June. Gaining confidence in the air will be their first task and as they slowly master the necessary skills, their first flying missions will see them relentlessly chasing their fellow siblings and parents. In those locations where three or more young have successfully managed to fledge, this can be an exciting time to watch Peregrines, as all the juveniles tear after any adult returning with food. The difference in flying ability between adults and young will initially be striking, but by steadily learning the vast array of tricks needed to survive, they will hopefully soon be up to speed. Able by now to dismember and feed on a complete carcass on their own, the youngsters will still be very much home birds and not dare to venture too far away from the site from which they hatched in late April.

Despite the oldest Robin ever recorded by the BTO being a bird from Fylde, Lancashire, which lived for over eight
years and four months, average life expectancy of the nation's favourite bird is thought in reality to be a meagre two years. With such a short lifespan, it's no surprise that Robins are keen to produce as many clutches as possible, meaning by the middle of June many pairs could already be well into feeding their second brood of the year. With daylight lasting over 16 hours by this time of year, the Robins will be keen to take advantage of these long summer days to keep their brood well fed. As with the first clutch, it will take the second brood no more than 13 or 14 days before the desire to unleash themselves on the world proves overwhelming. But as the speckled and helpless young will still need help from their parents for a further three weeks after fledging, the adults will have an important decision to make – whether to stick or twist!

As many Robins see their second brood fledging, those paired-up Swallows feeding the season's first young will also be constantly on the go as they attempt to keep up with their growing chicks' insatiable appetites. The emergence of the first pin feathers at around day four or five will coincide with the youngsters becoming even more ravenous. A couple of days later on and the chicks' ability to maintain their body temperature in all but the worst weathers will then see the female press-ganged into helping her mate find enough food to support their growing brood. A study of Scottish Swallows by Angela Turner recorded the number of visits made to a brood of five chicks back in 1980. At just a day old, the chicks were fed an average of six times an hour, which was then compared with 17 visits per hour at six days old and around 29 times an hour after 10 days.

In order to pack in so many visits, most adults will hunt close to the nest location, rarely foraging more than 600m away and frequently even closer. Where Swallows have
nested colonially, the feeding ranges of neighbouring birds will also overlap, particularly at traditionally rich feeding sites, such as around water bodies, or near cattle. The food the adults bring back to their chicks will also vary according to the time of year. Earlier in the season, for example, flies tend to be more abundant than aphids, and so for the first broods, horseflies and hoverflies are thought to form an important component of the chicks' diet. These large, mobile insects require more energy for the adults to hunt, so fewer can be caught on each foraging trip, but as they provide far more energy than smaller insects, it seems worth the extra effort to seek them out. When the adults are collecting insects for the chicks, they will usually catch a good number, which are packed together in a salivary ball (or bolus) in the throat, before returning to the nest. Angela Turner tried to count the number of insects in each visit, and recorded anywhere from just one insect to 126, with the average number amounting to 18. In order to rear a brood from hatching to fledging it has been calculated that the adults may need to catch as many as 150,000 insects. In addition to this high-protein invertebrate mix, the adults will also provide their chicks with grit to help grind up the food in their gizzards, so aiding digestion.

Fed on such prodigious quantities of food the chicks will grow quickly, with days three to ten being the period when weight gain accelerates the quickest. Flying in with food, it is the parents who appear to judge how hungry each chick is, with the intensity of begging a key factor, before then deciding who gets the meal. Certainly when food is plentiful, and during the course of the day, each chick is thought to receive a roughly similar amount of food. Both parents feed the chicks directly, but the male's effort can vary considerably between individual birds, with the more attractive longer-tailed males often being far more dilatory than the shorter-tailed males. This might not be entirely down to lethargy on the part of the longer-tailed males but
possibly due to being less efficient foragers as a result of drag created by their long streamers.

For the first few days of the Swallow chicks' lives any waste will be removed by the adults in the form of faecal sacs, but by 12 days of age, their toiletry skills will have improved sufficiently for them to begin painting the floor below the nest. After a couple of weeks the chicks should also be well feathered, and be topping the scales at 23 or 24g, making them even heavier than their parents. After this top weight has been reached, the chicks will then usually begin to lose a few grams as excess calories are burned by the constant exercising of their wings. Needing to fly competently the instant they fledge, they will still need a third week in the nest, during which time their flight muscles must mature sufficiently for them to propel themselves into the air when the moment comes. To ensure this first flight is a success, the chicks also spend an enormous amount of time preening to make sure they will be instantly flightworthy at take off.