Saturday, 26 August 2006

Modern parenting in Norfolk

This time last week I was at the Birdwatching Fair at Rutland Water, manning a stand promoting the BTO Garden BirdWatch. While the weekend itself was very interesting, it did mean that I missed the largest flock of dotterel to have visited Norfolk in nearly fifty years. This attractive wader breeds high up in the mountains of Scandinavia, Scotland and Russia. As such, it remains a scarce visitor to Norfolk, passing through in small numbers during its spring and autumn migrations. At least two-dozen of these delightful birds, and possibly as many as three-dozen, spent much of the weekend frequenting fields near Choseley Barns, which sit on the hill inland of Titchwell.

With smart grey upperparts, a white band across the chest and a rufous belly, a dotterel in breeding plumage is quite a sight. Remarkably (for a bird) the female dotterel is more brightly coloured than her mate, a trait that hints at an unusual approach to courtship and parenting roles. It is the female dotterel that initiates courtship, performing song flights to attract a mate. Once courtship is complete, the female will usually leave the male to incubate the eggs and rear the chicks on his own, while she is free to search for another mate. The roles of the two parents are determined by the different levels of investment in the reproductive attempt. Since eggs are energetically costly to produce, and sperm is cheap, it is unusual for a female bird to have the upper hand in determining the parenting roles. In this case, however, the female seems to have overcome any handicap.

The dotterel used to be more numerous when on passage through the county. Stevenson, writing in the late 1800s, noted that the species used to be so numerous that there was considerable profit in hunting it. Within Norfolk, the birds were netted, providing a great delicacy for the table. Some authors considered that the dotterel was easy to trap, a fact that may have had some bearing on its Latin name of “morinella”, which means “little fool”. The vernacular name itself shares a linguistic root with “dotard” again suggesting that the bird was rather stupid.

The general pattern within Norfolk is for more dotterel to be seen during spring migration than during the autumn one but, interestingly, the largest groups tend to be encountered during the autumn. A record 47 were seen together at Terrington Marsh on 20th August 1959, while the largest group seen in more recent years was 17 near Docking on 26th August 1996. These small groups of dotterel are known as “trips”. It’s just a shame that I couldn’t make the trip back from Rutland in time to see them last weekend.

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