Wednesday, 30 March 2016

Secrets of a small rookery, part two: Nest-building in an unlikely place

Why do the Southover Rooks nest along a busy road in Lewes?

An insight might be provided by an anecdote involving American Crows observed over a period of years at the University of Washington in Seattle (Marzluff & Angell, 2005). The crows gathered en-masse each morning on the black tarmac of a large parking lot. Wave after wave of crows gathered on the lot. No food or water were present and a theory that the tarmac helped them warm up in the mornings was disproved by temperature readings. Eventually, an elderly Seattle resident informed the observers that the area used to be a landfill site some forty years before and that the crows used to gather and feed on the garbage there. This suggested a promising explanation for the mass gathering on the parking lot: the location could have been a part of the crows' local culture as a former rich source of food which has been passed down through the generations. They had always gathered there.

Referring back to the Southover Rooks, as unlikely as the location of the rookery between Southover Road and the railway line might seem today, it is possible that it was once a larger rookery in a less urban setting and that the Rooks have chosen that location as a nesting site all the time that there have been trees and a local food source. It would be difficult to prove that the rookery is ancient, but it is tempting to speculate that the Southover Rooks have been looking down from the treetops at Lewesians since before the coming of the trains. Perhaps they even watched the erection and dissolution of the Priory, at a time when the Dripping Pan was too saline for Rooks?*

The Southover Road Rookery in Lewes is a modest one. As soon as I see the litter of fallen nest material on the pavement below, I keep a weekly account of nest numbers until around mid-April, when they disappear into leafy privacy for the summer. I have counted the numbers of nests for several years and this is what I have seen:

2011: 35 nests

2012: 24

2013: 31

2014: 34

2015: 30

There are twenty seven so far this year and this number will continue to rise until about late-April.The rate of nest building has been steady this year since I started counting on 29th February. Progress has been noted on the following dates:

29th February: 9 nests

14th March: 17

21st March: 22

29th March: 27

The totals from previous years suggests that the appearance of new nests will slow over the next couple of weeks and they should be completed by the time the swelling buds on the elm and sycamore trees burst into leaf, concealing them behind a green curtain for the breeding season.

There are much larger rookeries dotted along the Ouse valley south to Newhaven. A larger one at Iford contained 71 nests in 2011. The greatest rookery I know of in the Seahaven and Ouse Valley areas is at Bishopstone, where the nest site is so extensive that it has been beyond my capability to fully count the nests. According to my notes, there were a minimum of 300 mixed Rook and Jackdaw nests in 2011, which is presumably the point at which I lost count. I have counted a minimum of 94 nests to date this year, but this is from a distance and is not a reliable figure because I am able only to see a fraction of the nests at this truly magnificent site. The woodland forming the nest site is called The Rookery; the hill above it Rookery Hill and a residential road nearby, just over the hill to the west, is Rookery Way. The rook has named more roads and more villages in England, apparently, than any other bird and it is clearly embroidered into the Bishopstone landscape. It seems that they are rooted in our culture as well as to the land, regardless of how we feel about them.

Fifteen of this year's Rook nests at The Rookery, Bishopstone

*The Dripping Pan, home to Lewes Football Club, nicknamed 'The Rooks', was used as a salt-pan by the monks of the Benedictine Priory of St. Pancras before its dissolution in 1537.

Reference: Marzluff, John M. and Angell, Tony (2005), In the Company of Crows and Ravens, Yale University Press: New Haven.

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