1.      Optimum breeding habitat for little tern is unvegetated shingle ridges.  At Gibraltar Point, there is extensive shingle on the ridges and spits at the southern end of the NNR and along the Greenshank’s ridge, stretching north to beyond the NNR boundary.  The dispersed and linear nature of the colony along this stretch of coast, provides a management challenge. Little terns nest along the full length of the available shingle.  Fortuitously, the densest population occurs on the shingle ridges and plateaux at the southern end of the reserve. This may be partly attributable to continued low productivity of nesting pairs to the north.  At the south end, the quality and extent of shingle has been optimum during the late 1990’s, but embryo dunes have started to accrete over the core colony site and may cause a shift of activity.  Colonisation of the developing Millennium Ridge (compt 1/11/F), may occur pending the suitability of shingle.

2.  Little terns are dependent upon healthy coastal waters with adequate populations of fish and crustacea.  A feeding study carried out in 1978 determined that the species was 80 % dependent upon crustacea (Davis 78) but more recently, visual observations suggest that fish, particularly sand eels comprise a significant part of their diet.  The possible change may have been forced by population changes in the brown shrimp Crangon crangon.  This species is caught commercially and in good years, twin-beamers trawl just offshore at quite high densities.  From 1990-1994, low chick survival was partly attributed to starvation. Subsequently however, food availability (particularly sand eels) has been high on this sector of the Wash.  Adult and juvenile little terns have been noted shoal-fishing occasionally in August.  Large numbers of sandwich terns have also accumulated at this time to exploit the situation.  Target prey species are routinely monitored by Eastern Sea Fisheries.

3.  Nesting activity is usually underway by late May, with the first clutches around 22nd.  If a first clutch is lost, then pairs will relay a second and sometimes a third time.  Highest productivity is generally associated with the early clutches, particularly as there is less predator pressure and daylight hours are longer for feeding.  Egg predation by crow, magpie and fox, have accounted for substantial losses in some years.  Where a compact colony has established, the mobbing efforts of a large group of terns is a strong deterrent to corvids, particularly if a pair of oystercatcher are involved. Isolated pairs in contrast will have less chance of protecting their clutch.

4.  Historically, the decline of the UK little tern population has involved man.  The visitor pressure in coastal habitats developed in association with a boon in post-war travel and tourism.  Inevitably, damage and disturbance increased on sensitive habitats and species. Furthermore, the effects of egg collectors has played a part.  The threat of this practice is still very real today.  All eggs from 27 pairs of little tern were stolen from a site in Cleveland in 1998.  The birds failed to return the following year.  In 1992, the loss of several clutches of ringed plover was attributed to egg collectors at Gibraltar Point.  Operation Compass is an East Anglian initiative involving the police and local conservation organisations to provide and early warning system of egg collector activity in the region.

 

Halcrow have been instructed to carry out detailed monitoring of the geomorphological processes on the reserve and how they are being influenced by beach nourishment through the Lincshore project.  Survey work is advocated between September and March to avoid undue disturbance during the nesting season.

5.  Shingle ridges offer a fairly inhospitable environment for nesting.  In some years, clutches may be lost when they become sandblown during north-easterlies in particular. Long- periods of inclement weather may also cause chicks to perish.  Flotsam and jetsam are used for shelter and artificial chick shelters may be provided.  Successful breeding may be impeded through tidal inundation, where low-lying shingle is selected for nesting.  Spring tides over 6.8 m (sometimes less) will start to inundate key nesting sites. Clutch losses to high tides is a factor in most years.