Little Terns Sternula albifrons are unusual among UK seabirds in that a large proportion of the population breed on mainland beaches in East Anglia. Relative sea-level rise means that such habitats are under threat in this region, and so we quantified colony habitat selection of beach nesting Little Terns in order to inform habitat restoration and creation initiatives. Random 1 km sections of beach were selected and the presence or absence of a Little Tern colony within each was related to physical (substrate type, height and width), biotic (vegetation cover, predator activity) and anthropogenic (disturbance) characteristics using logistic regression models. Little Terns positively selected for beaches with vegetation cover and negatively for those with high disturbance levels. They showed no selection according to width and height or Red Fox Vulpes vulpes presence, even though these are likely to affect flood and predation risk respectively. Red Foxes were found to be widespread on beaches irrespective of tern colony presence, and so movement of tern colonies will not always result in predator avoidance. Little Tern habitat creation needs to be integrated into coastal management plans in order to safeguard their population from the combined threats of relative sea-level rise, predation and disturbance.

The population size and range of Little Terns Sternula albifrons in the UK have declined by 24% since the mid 1980s (Pickerell 2004), and qualifies it for inclusion on the Amber list based on a moderate rate of population decline (Gregory et al. 2002). It is also listed on Annex I of the Birds Directive (EC Directive on the conservation of wild birds 79/409/EEC) and 67% of the GB population lies within Special Protection Areas (Stroud et al. 2001). Little Tern distribution through the UK has been broadly stable since the 1960s, being wide and patchy with a stronghold in East Anglia where 69% of the population currently breed (Pickerell 2004). There is an absence of sandy offshore barrier islands in the UK, and so Little Terns nest mainly on low-lying shingle beaches, spits and estuarine islets, and here they face threats from disturbance by coastal tourism, predation and inundation by high tides or storms (Ratcliffe 2004). These threats are mitigated to varying extents by intensive colony protection schemes (Smart 2004) that currently cost conservation organisations tens of thousands of pounds per annum, and need to be run in perpetuity in order to maintain Little Tern populations. Furthermore, the colony habitat of Little Terns is under threat from relative sea level rise and increased storminess (Norris & Buisson 1994; Gill 2004), such that protection of existing colonies from disturbance and predation may be inadequate to conserve them in the future.

Rather than continuing to focus on colony site protection, a strategic approach to the management of Little Tern distribution relative to threats may result in more effective conservation. Little Terns require small areas of habitat that can be restored or created quickly and inexpensively, and these can be sited in areas where threats to breeding success are lower. For example, creation of dredge spoil islands offshore could reduce predation and disturbance without need for fencing and wardening (Parnell et al. 1986; Burgess & Hirons 1992; Erwin et al. 2001), and sediment recharge of eroded narrow beaches could mitigate loss of habitat or colony flooding risks (Charlton & Allcorn 2004). The characteristics of Little Tern colony sites need to be quantified and means of creation or restoration have to be tested in order to achieve this (Gill 2004).

Shoreline management plans are currently under review for East Anglia and decisions are being made that will affect coastal habitats in future decades. These decisions are mainly influenced by engineering and economic considerations at present, but it is important that conservation requirements are also included (Gill 2004). A strategic review of Little Tern habitat requirements would be timely in order to influence coastal planning decisions in a manner that is sympathetic towards Little Terns and to exploit opportunities that may arise as a by-product of managed realignment or coastal defence (Gill 2004).

This project examines colony habitat selection by Little Terns in relation to beach characteristics, including width, height, shoreward habitat type, substrate type, disturbance and predation risk. The implications of the results for habitat management and creation are discussed and recommendations for further research are made.

This work was funded by a partnership between RSPB and English Nature. We are grateful to the wardens of tern colonies in Norfolk and Suffolk for granting permission to work on their sites and for assisting with data collection. The Environment Agency kindly provided access to the beach profile data. We thank the two anonymous referees for constructive criticism of an earlier draft.

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