Nightingales in November (39 page)

Compared to Waxwings, the Puffin parents will have to make far longer foraging trips during the breeding season if they are to locate sufficient food for their single chick back on dry land. How far the Puffins travel to catch fish for their subterranean Puffling was, until recently, little more than educated guesswork. Research work carried out on the large Skomer colony, in west Wales, found 85% of Puffins recorded within 15km of the island were carrying fish out at sea, meaning these must have been birds returning back with food for their chicks. However, on the remote islands of St Kilda off west Scotland, the researchers had to travel 40km from the islands before the majority of Puffins were seen to be carrying fish, suggesting that the birds may have to forage at greater distance. More recently seabird researchers Mike Harris and Sarah Wanless have successfully managed to attach GPS (Global Positioning System) loggers to a number of Puffins on the Isle of May, situated at the mouth of the Firth of Forth in east Scotland, and found that the average distance the Puffins were travelling to feed was 38km, with a maximum recorded of 64km – a long way indeed for a fish supper!

Fish are of course never evenly distributed across the seas and oceans, but distinctly clumped, and so finding the discrete shoals of fish in the vast open spaces of the North Sea, Irish Sea and north-east Atlantic Ocean could potentially be very difficult. It seems, however, that Puffins, through trial
and error, must be able to quickly familiarise themselves with the best feeding areas. Despite being intensely sociable birds on dry land, Puffins seem to shun company at sea by keeping spaced out across any possible fishing areas. It's believed that each Puffin dive will rarely last longer than a minute, with the bird then taking a brief rest on the surface before slipping below again. Using time-depth recorders attached to Puffins, Sarah Wanless and her colleagues recorded one Puffin making an astonishing 194 dives in 84 minutes, which suggests that the Puffins don't dive anywhere near as deep as Guillemots and Razorbills, for example. Below the water Puffins suddenly become transformed into lean, mean swimming machines as the pressure compresses their feathers flat to the body and the wings are suddenly transformed into powerful flippers able to propel the bird through the water at a surprising speed. With the feet acting as both rudder and stabilisers, their manoeuvrability is another tool in the armoury helping them to snatch any unwary prey.

Further results from four time-depth recorders attached to Puffins feeding chicks revealed that, on average, each bird made 1,148 dives per day and spent 7.8 hours under water. From this revelatory data it has been extrapolated that Puffins may catch a fish on only two out of every five dives, and so energy-demanding is this occupation that 90% of all the fish they catch will be purely for their own consumption, with no more than 10% destined for the chick waiting back in its burrow! Of course, unlike the Blue Tits feeding their chicks, which will return to feed their young with a single caterpillar each time, Puffins are famously able to carry many fish at a time. This ability to catch more fish while still holding on to the ones already caught is achieved with backward-pointing spines, called denticles, on the roof of the mouth. Adopting the ‘belt and braces technique', any food caught is prevented from being dropped by a rough covering at the back of the tongue, and finally the load
they're able to carry is also maximised with the help of a flexible hinge between the lower and upper mandibles.

With Sandeels being the main prey for British Puffins, the number they're able to carry will vary between colonies, different pairs and from year to year. Billfuls of between four and twelve seem the norm at many colonies, but an unbelievable 61 Sandeels and a Rockling observed being carried by one bird returning to feed its chick on St Kilda is frankly astonishing. Historically, there was a suggestion that the Puffins arranged the fish to be positioned alternately in the bill, so that the head of one fish would be placed adjacent to the tail of the next and so on, but in reality the fish are carried in a haphazard fashion and presumably held in the same orientation as when the fish was originally caught. However they're arranged, once the adult is content it has caught a sufficient number, it will then head back to the puffinry, where it must face one last challenge before the chick receives the reward its patience deserves.

Having now hatched around twelve weeks ago, the juvenile Tawny Owls, like the Pufflings, will still be reliant on their parents for providing 100% of their dietary needs. Despite being fully mobile, fledged young from the same nest will still frequently choose to roost close together at a few favoured spots as they wait for their parents to bring in food. It seems the parental care that the adult Tawnies provide is confined to the provision of food and defence against predators, with little evidence that they actually train their young how to hunt or catch prey. This is a different ethos to Peregrine Falcon parents, which take the tutoring of their offspring very seriously when it comes to passing on best hunting practices. Once their young have begun to master the art of aerial food-passes, the parents will then move on to delivering live birds. These usually tend to be feral pigeons that the parents have
already caught alive, only to be released, possibly in a dazed and confused state, as catching practice for the young. Initially there are plenty of near-misses as the quarry either escapes or has to be subsequently recaptured and killed by the parents, but the youngsters will soon become proficient at catching and dispatching the prey item with the minimum of fuss.

As the young Blue Tits begin to disperse further afield from where they were reared, they will not be figuring prominently on any Peregrine Falcon's radar, but much higher on the list of any local Sparrowhawk, which would jump at the chance of an easy meal of a ‘naive fledgling' or two. In addition to running the very real risks of predation, the number of caterpillars in the trees may have already passed its peak too, leading to starvation and any diseases brought on by being in poor condition, which can be major stumbling blocks during this seeming ‘time of plenty'. However, there is substantial help for the many Blue Tits which fledge from suburban locations, thanks to easy feeding opportunities offered up in many gardens. Certainly in the south of Britain, most gardeners who regularly leave out peanuts and sunflower hearts can be sure of seeing a steady stream of juvenile Blue Tits in the early part of the month. Distinctive with their greenish caps and yellowish cheeks, many juveniles can now be seen dashing from the cover of the surrounding bushes to the feeders as they attempt to grab an easy beakful of food.

Any adult Blue Tits freed from the constraints of looking after their young should by now be able to concentrate on finding sufficient food to fuel their annual moult, which could carry on at least up to early September. Of course, adult Nightingales will not have the luxury of being able to carry out their wing
moult in such a gradual fashion as their flight feathers will be needed to power them to Africa, and so a rapid moult will make them far less mobile at this time. Needing to keep flight to a minimum, it's thought that the adults will choose sites away from the breeding grounds, which offer both rich feeding opportunities and plenty of places to hide away from any predators during this perilous period.

Having also deserted their breeding grounds, the adult Lapwings and any fledged juveniles will by now have been absorbed into large, mobile moulting flocks. As good feeding opportunities for these flocks in summer may be both widely spaced apart in the countryside and ephemeral by nature, the Lapwings will need to ensure they're able to stay aerial. This of course means – like with the Blue Tits – that the wing moult is a long, drawn-out process, not finishing until early September. Also needing to be prepared for the rigours of winter ahead, the juveniles will begin a partial moult by shedding some of their fledging feathers. Clearly distinct with their short crest, buff face, scalloped back and wing feathers and incomplete breast-band, the juveniles will also show a shorter wing than fully adult birds with a clearly narrow primary area in flight. It will not be until December, and some seven months after hatching, that they will finally be looking pretty similar to the parents that successfully raised them earlier in the year.