Find us on Facebook   HM Harbour Master at Wells Norfolk on Twitter
Find us on Facebook and
follow us on Twitter

 

Little Tern Survey 2012
Fri 31 Aug 2012

Back

For the third year bird expert James McCallum has been commissioned to carry out a monitoring survey on bird behaviour and breeding around the Harbour Channel. This was commissionerd in order to provide comparison data which, however, was not required under the maintenance licence conditions.

Here we report on what James found.

From early May to August 2012, James carried out a detailed survey of Little Tern breeding activity concentrating on the shingle and shell ridges to the east of the main channel on Bob Halls Sands and the Outer Harbour berm. The same methodology was followed as in 2011, originally set out by Royal Haskoning who commissioned the original survey in 2010. During the observations on Little Tern behaviour and breeding attempts, James also collected information on other nesting species such as Common Terns, Oystercatchers, Ringed Plovers, Black-headed and common gulls. Little Terns are a schedule one breeding bird and are therefore legally protected. In order to avoid any disturbance to them on their nesting areas James watched them from a distance using a telescope with a 15 x 40 zoom lens.

Part of the reason for the survey was to check for any disturbance caused by vessel movements or the channel dredger, Kari Hege. Both Little and Common Terns were noted as fishing in the channel when the dredger was working, and although neither species feeds closer than 90-100 meters, James reported that the dredger did not appear to trouble either species. It is good to report that terns are actively using the Channel and the Outer Harbour for feeding.

The smallest of the terns found at Wells are the Little Terns. They have a black and yellow beak, a shrill cry and almost white wings. Weighing only about 50 grammes these birds migrate as far as West Africa in the winter - one ringed Norfolk bird was recorded in Senegal - and with just 1900 pairs in the whole of the UK, they are a closely protected species.

The 2012 survey was one of great contrasts. Whereas all birds nesting on the traditional breeding ridges on Bob Halls Sands or East Hills suffered complete failure due to surge or spring tides, those using the eastern wall of the Outer Harbour fared much better. The Little Terns in particular experienced an excellent breeding season where approximately 19 pairs on the Outer Harbour berm fledged a minimum of 9 young. This is excellent news as James only recorded two young Little Terns that successfully took wing in 2011 from the southern of the two shingle ridges of Bob Halls Sands and none at all in 2010. Six pairs of Common Terns also nested on the Outer Harbour berm for the first time and fledged 5 young, whereas the 34 pairs breeding on Bob Halls Sands failed to fledge any young. Calculating the exact number of nesting Little Terns is notoriously difficult as there is frequently an ongoing cycle of predation and new breeding attempts. Many birds make several breeding attempts and new pairs often also arrive. Without colour ringing the birds, arriving at an exact total is near impossible, but James is confident that his estimate of 19 breeding pairs of Little Terns is quite accurate.

James wrote in his notes:

Tern Feeding behaviour – The feeding behaviour of the Little and Common Terns followed a distinct pattern that mirrored the findings of the previous two surveys. One aspect of feeding that was however noted in 2012 and not in 2010 or 2011 was the occurrence of trapped shoals of both Whitebait and Lesser Sandeels during certain ebb tides. The trapped fish quickly attracted the attention of both terns and gulls. Large feeding groups frantically fed on the trapped fish until the supply was exhausted. This situation although highly erratic in occurrence could be observed regularly until at least early August. It was most often observed just to the south of the Outer Harbour.

The following details the pattern of both Little and Common Terns in Wells Harbour. At high tide many birds are seen to be resting or small numbers fishing around The Bar or in the open sea. During rising and falling tide there is far more feeding activity, much occurring in the lower reaches of the channel (particularly on the eastern shore) especially around The Bar or in the open sea. Smaller numbers of both species may be seen south of the Lifeboat house. The Common Terns may be seen fishing as far up the channel as the Whelk Sheds and Little Terns regularly frequent the smaller creeks. The channel north of the Lifeboat House is, however by far the most important feeding area in Wells Harbour. At low tide the majority of both Little and Common Tern fishing activity takes place in the open sea. During the survey, Whitebait and Lesser Sandeels were the most commonly recorded prey items for both species. Both Little and Common Terns were occasionally seen bringing in Common Gobies and on two occasions a Common Tern was seen bringing in a Common Prawn.

Other species of birds were recorded during the survey. Five pairs of Oystercatcher were noted on Bob Halls Sands but failed to fledge any young, however one pair on the Outer Harbour berm fledged one young. Two of three pairs of Ringed Plover on Bob Halls Sands laid eggs, and both pairs on the Outer Harbour laid eggs, one brood of chicks were seen but all were thought to have been predated. Twenty two pairs of Black-headed Gull laid eggs on Bob Halls Sands of which one pair probably hatched chicks. Six pairs laid eggs on the Outer Harbour berm of which three pairs hatched chicks. The outcome of the young is not known.

Wells Harbour Commissioners are confident that the results of the last three years surveys confirm that the Port’s dredger Kari Hege and other vessel movements have no detrimental impact on the feeding or breeding activities of birds in the Harbour. The Outer Harbour has proved to be a more protective and productive habitat. It is imperative that birds breeding on the berm of the Outer Harbour are left undisturbed and the biggest threat to this environment is the general public and loose dogs causing a nuisance. Wells Harbour Commissioners will look to improve the protection of the Outer Harbour and erect more signs in 2013.

If anyone wishes to read the full report this can be accessed on the environmental page of the website.

James McCallum is a wildlife artist living and working in North Norfolk. For information on his paintings and books, visit www.jamesmccallum.co.uk
    Click here for access to full report

Back