Read Nightingales in November Online
Authors: Mike Dilger
By early April, most female Kingfishers in southern Britain will have begun to lay their first of possibly two or even three clutches deep in their subterranean nest chamber. Laying an egg a day, most clutches will consist of six or seven shiny, white and round eggs, measuring around 23mm across and weighing in at marginally more than a 1p coin. Only once the clutch is complete will incubation begin in earnest, and despite the female putting in longer shifts both parents will take their turn. When not incubating, the other bird in the pair will spend its âdowntime' either patrolling the territory or fishing.
From the moment the birds start incubating, the river tends to instantly become much quieter, but both birds will still defend their patch, and should any intruder be discovered during this period the incumbents will explode into defensive action. Exactly this type of territorial dispute was filmed by wildlife cameraman Charlie Hamilton James for his
Natural World
film entitled
My Halcyon River
. Airing on the BBC in 2002, one particular sequence has surely become one of the most memorable moments of wild behaviour ever filmed in Britain. Charlie was busy filming his local Kingfishers and managed to capture the moment that a trespassing female was caught in his resident pair's territory. Upon spotting the trespassing bird, the resident female immediately went into attack mode and, as neither bird backed down, both quickly ended up locked in mortal combat as they tried to drown each other. While this commotion was carrying on, an American Mink then suddenly dashed out of the waterside vegetation, and into Charlie's shot, before
grabbing one of the Kingfishers, which was immediately dispatched and presumably stashed before the mink returned for Kingfisher number two. In the meantime, the surviving Kingfisher, which fortuitously happened to be the resident female, had managed to scrabble out of the water and to safety above ground. Even if
we
think it's a quiet time for the Kingfishers, it may in fact be anything but!
As Peregrine eggs usually take between 31 and 33 days to hatch, early April should see many urban Peregrine pairs around halfway through the incubation process. As the female carries out most of the incubating duties, the male will also need to hunt for his mate during this period. Flying in with prey, he will then either execute an aerial food pass with her or bring the item to one of her favourite perches away from the nest site. Peregrine supremo Derek Ratcliffe thought that a high proportion of kills at this time, certainly in rural nest sites, were made by the male early in the morning, and while the female fed, he would then take a turn to incubate the eggs. During the whole incubation process the only time that the eggs are believed to be left uncovered is when the female briefly leaves to preen, defecate or even hunt, if the male is either not pulling his weight or weather conditions are making catching prey difficult.
After the essential prerequisites of courtship, scrape adornment and copulation, the female Lapwing will be free to begin laying, with four eggs being the most common clutch size. Taking anywhere from four to eight days to produce her clutch, the distinctive eggs are âpyriform' or pear-shaped, and invariably arranged so that the distinctly pointed ends face
inwards. Unlike the eggs of Tawny Owls and Robins, which due to their pale, unspotted nature would stand out like a sore thumb in open country, the Lapwing's clutch has evolved to blend in with the immediate surroundings. This effort to actively camouflage the clutch is helped by the eggs' background pigment of pale brown or clay, which is then furnished with numerous black blotches, streaks and spots to break up their outline. Weighing in at around 25g each, the eggs are proportionately large for the size of the bird, meaning a clutch of four could potentially weigh close to 40% of the female's entire body weight â a huge physical investment on her part.
For Lapwings, incubation will only begin when the last egg is laid, and in common with birds as diverse as Peregrines and Kingfishers, even though both sexes are able to incubate, it's the female that takes both the larger share during the day, and the entire night session. For those females that plumped for a polygynous male, their incubating share may be even greater due to his attentions being pulled in at least one other direction.
With the nest complete, and mating largely dispensed with, the female Robin should also now be laying her clutch. Only visiting the nest for short periods at this stage, an egg will be deposited each day, with the time slot between 6am and 8am most favoured. Robin eggs are mostly white and speckled with small reddish-brown spots, although the background colour can occasionally be a pale blue or yellow. Each female Robin does seem to have inherited just one egg colour, however, with the result that all eggs in the same clutch should look similar. Like the Tawny Owl, and in fact most cavity-nesting species, the Robin's eggs do not of course need to be coloured for camouflage. Amongst British Robins, five appears to be the most common clutch size, although four, six, seven
and very occasionally even more have been reported. Interestingly, clutches of six seem to be more common amongst Scottish Robins in May and June, and may be due to the longer daylight hours, giving the parents more time to forage for that extra beak. As soon as the final egg is laid, the female will then be intent on keeping a very low profile for the following 14 to 16 days of incubation, in order to avoid any unwanted attention from a whole variety of hungry predators.
Having only just built up the confidence to land at their nesting colonies, the first Puffin eggs will probably not appear for at least another three weeks yet. Initially very nervous on land, the vanguard often form âclubs' on exposed rocks, which the birds will use as staging posts while keeping a collective eye out for predators. Spending the breeding season in a packed nesting colony means that Puffins have had to evolve a whole array of ritualised behaviours to convey messages to both their mate and immediate neighbours, one of which is the âpost-landing gesture'. This behaviour involves placing their body in a more horizontal position with their legs slightly bent and wings held aloft and above their back; this is thought to be deployed by any bird that has just flown in to appease all the other surrounding Puffins.
Unlike other colonial auks like Guillemots and Razorbills, which are primarily ledge nesters, the Puffins prefer the sanctuary of nesting underground in burrows. Upon arrival at the colony, and with their confidence boosted by their membership of the âclub', they will then start briefly peeling away in order to conduct mini inspections of any nearby burrows. This âbranching out' is conducted in the full knowledge that if any danger is sensed, they will still be able to either quickly take to the air or run back to the club. Those Puffins that have previously bred within the colony will typically first check out the very same burrow they will
have used in previous years. At thriving puffinries the competition for nesting locations can be intense, with experienced birds fiercely defending what they perceive to be their own property. Any returning owner coming back to a previously occupied burrow, only to find a prospector sniffing around, will swiftly switch into full eviction mode. Puffing itself up and half spreading its wings, the aggressor will open its beak in a menacing gape, and if this doesn't have the desired effect, it will quickly pick a fight. Using its bill and feet as the main weapons, any ensuing scrap is often short and sharp, leading to the possession of the contested burrow being quickly resolved once and for all. Victory complete, the conquering Puffin will then declare his site ownership to all onlookers with a âpelican walk', which involves standing upright, with his bill pressed to his breast feathers, while conducting a slow, exaggerated walk.
As the Puffins reacquaint themselves with their burrows, it will also be crunch time for the Cuckoos, which after feeding well in the Ivory Coast will be able to delay their crossing of the Sahara Desert no longer. Until his unfortunate demise in the summer of 2015 Chris the Cuckoo was successfully followed on his northward journey by satellite on three occasions. During those three migrations his departure point for the Sahara, and all points further north, has varied, being twice from Ivory Coast and once from adjacent Ghana. However, he always left within a small time-window of ten days â with the first of his âdesert days' falling each year between 1 April and 10 April. Chris's departure dates also seem to tally with the movements of many of the other Cuckoos tracked as part of the BTO's research programme.