Scientific name: Tringa erythropus
UK numbers: c400-600 on passage, c100 wintering
Habitat: Coastal and inland wetlands
Diet: Mainly aquatic invertebrates, some small fish
There is an old Finnish saying that goes as follows: “Voit asettaa kellosi mustaviklo.” It is spoken across the heathlands, tundra and open forests of the north of that country, as the locals meet to converse; much as British people outdoors might discuss the vagaries of the seasons. The phrase has a quaint quality, but it echoes a deep understanding of the sub-arctic and arctic environment. Roughly (Google-) translated, it means “You could set your watch by a Spotted Redshank.”
To be honest, I completely made that up. With due apologies to any Finnish readers, there is no such phrase. However, there should be, because of a very fascinating and unusual quirk of Spotted Redshank migration. It is perhaps the finest example in Europe of an Instinct Migrant.
Although the term isn’t used much these days, an Instinct Migrant is one that arrives on time, like clockwork, regardless of meteorological events, and it also departs promptly, as if following a timetable in its head – which is, in fact, exactly what it is doing. An Instinct Migrant is more accurate and reliable than a migrant which is more adaptable to weather conditions, or more likely to be delayed by unexpected difficulties.
Of course, no bird migrant is ever entirely perfect. However, a study published in 1979 found that Spotted Redshanks historically arrived in Finland within the span of a week, between 1st and 8th May, entirely predictably, and all had settled over the country in days. Most bird species show nothing like this kind of discipline. In the UK, most species arrive over the course of weeks. It is clear that Spotted Redshanks have their schedule in their heads.
On the move
When it comes to the departure in autumn, however, the pattern is even more fascinating. Once again, Spotted Redshanks leave at a predictable time in the ‘autumn’, within a smaller range of dates than other waders or, indeed, most other landbirds. What is different after breeding, is that certain categories leave at different times. The females leave first, in the second week of June. They are among the very earliest European species of bird to depart their breeding areas, having stayed up north for only three or four weeks – Green Sandpipers are the same. The males leave more than a month later, and the juveniles later than this, well into August. There are some variations, but Spotted Redshanks are much more predictable than most other birds in their departure. There is an element of OCD wired into their migratory timetable.
Having read the above, you are probably wondering why the female Spotted Redshanks leave so much earlier than the males. This highlights another interesting facet of this wader’s behaviour, the division of labour between the sexes. Many people seem to have an ingrained idea that female birds share a greater burden of parental care than males. This is sometimes true, but the reality is always more complicated than that. However, it is perhaps refreshing to know that some species truly buck this trend, imagined or not, and one of these, emphatically, is the Spotted Redshank. On the breeding grounds, fresh from their well-timed arrival, the males and females have a brief and, by all accounts, not very committed courtship, forming a pair bond of convenience. And by the time the eggs are laid, the burden falls upon the male. The male is responsible for almost all the incubation. In fact, it is thought that females which complete the clutch of four will sometimes immediately abandon their first mate and pair up with another male.
Before the end of incubation, usually a week before hatching, the females give up the pretence of parental interest entirely and form hen-flocks, which very quickly depart south for, one assumes, a spot of well-deserved post-breeding moulting and hassle-free feeding. Very quickly they turn up on British lagoons and sheltered estuaries, usually in small numbers. At this time of year, they will often look dishevelled and confusing.
Meanwhile, the males await the hatching of the chicks, which they lead to sheltered feeding areas on the forest tundra, where the young can feed themselves straight away. The chicks then take four weeks to fledge, a significant amount of effort for the single parent, at least in terms of keeping vigilant. It is only in the second half of July that the males finally retreat a short distance south.
Some swell the small numbers of birds in Britain. In an average year, only about 420 of these attractive waders are recorded here. A few birdwatchers might rue that any ‘Spotshanks’ turn up at all, because they add to the befuddling mix of autumn wader pitfalls, which can lead to red faces as well as shanks. The juveniles, in particular, can look very similar to Redshanks, especially of the same age. However, after a while, most of us begin to ‘get’ this species, not because of its plumage but because of its typical feeding behaviour, which is distinctive.
In one of those wonderful studies whose existence is proof that there is joy in the small details of life, back in 1953, somebody called DB Peakall spent many hours taking readings every two minutes of the precise depth of water in which Spotted Redshanks were feeding. Of the 673 samples, 1.5% were on dry land, 23% were in shallow water (as far as the bird’s ‘knee’, the tibiotarsal joint), 51% were above the joint but below the belly and 26% were in deep water up to the belly. The obvious conclusion is that Spotted Redshanks like to feed in relatively deep water, and in that regard they are significantly different from Redshanks, which feed for much of the time out of the water (unfortunately there isn’t an equivalent study with percentages.)
What this means is that, should you see a Redshank type up to its belly in water, it is well worth checking. If you see several similar birds also doing the same thing, that is telling. And if you should see these birds swimming like ducks and even upending in the water (head down, bottom up), then they are almost certainly Spotted Redshanks, not Redshanks.
At other times they will behave like an Avocet tribute band, wading through the water and sweeping the bill from side to side, in the same manner as the black-and-white superstar. Spotted Redshanks are among the few waders that regularly eat fish (Greenshanks do, too), although their main diet consists of the usual wader fare of worms, crustaceans and molluscs (with some insects thrown in).
By October, most birds have completed their moult and left our shores to winter further south, mainly in North and West Africa. A few remain behind to spend the off-season in brackish lagoons and estuaries, mainly in the south of the UK.
In our sad and warming world, the fastest and greatest impacts of climate change are likely to be seen in the arctic and sub-arctic regions. These immense but fragile environments could quickly collapse, and the habitat of birds such as the Spotted Redshank will diminish, and possibly crash. The outlook for this species is bleak in the long-term.
Already, the unthinkable has happened. A study in the early 2000s found that Spotted Redshanks were beginning to arrive earlier on their breeding grounds. However instinctive this migrant may be, even the migration pattern in its brain is changing. And that is a frightening thought, indeed.
Where to see them
Mainly seen on passage (with some wintering)at coastal wetland sites, when often preferring fresh or brackish water. A few are also seen inland, mainly on passage.
The timing of arrival and departure of the Spotted Redshank_Tringa erythropus_in Finland O Hildén - Ornis Fennica, 1979 - lintulehti.birdlife.fi