Little Tern (Sternula albifrons)

Little tern (Sternula albifrons) are a very small tern. Adult breeding plumage consists of pale grey upperparts and white underparts, with a black cap and small white forehead. They have short yellow legs and a yellow beak with a dark tip (fig. 1) (Svensson et al, 2020). Little tern nest in loose colonies on sandy shingle with short vegetation. Their diet largely consists of small fish, and some crustaceans and marine invertebrates. Little tern typically live to around 12 years old, breeding at 3 years (Harris et al, 2024).

Population & Distribution:
Little tern are a summer visitor the East Grampian Coast, arriving in small numbers to breed at Forvie National Nature Reserve (NNR). Around 1-2% of the global little tern breeding population is hosted by Britain and Ireland, with around 13% of this population found in Scotland (fig. 2) (Burnell et al, 2023; Harris et al, 2024). Over the years little tern have been recorded breeding in two areas along the East Grampian Coast: Forvie NNR and St Cyrus (fig. 3 & 4). Since 1987, there has only been one pair recorded attempting to breed at St Cyrus in 2007 - fledging no chicks. There has been no breeding records since this time, and it is believed the site has been encroached on by dunes. Forvie NNR is now the only area regularly hosting a breeding colony along the East Grampian Coast (fig. 5), although numbers fluctuate annually and breeding success is highly varied.

Conservation Status:
Little tern are an Amber listed species due to a moderate breeding population and range decline, and breeding localisation (Stanbury et al, 2024).

Factors Impacting Little Tern:
As little tern are a ground nesting species, their chicks and eggs are vulnerable to predation from red fox (Vulpes vulpes) alongside large gulls and birds of prey such as kestrel (Falco tinnunculus)  (Harris et al, 2024). Over the years the breeding success of the little terns at Forvie has been highly variable and this has largely been attributed to predation pressures from species such as foxes, black-headed gull (Chroicocephalus ridibundus) and oystercatcher (Haematopus ostralegus) (Macdonald, 2022).

Along the East Grampian Coast breeding success of little tern has also been hampered by poor weather, particularly heavy rain, which has resulted in chick mortality. 75% of suitable shingle habitat for the little terns was lost at Forvie due to winter storms over 2021-22 which may have an impact on future breeding attempts (SOC North East Scotland Branch, n.d.)

No mortality has been recorded in little tern from Highly Pathogenic Avian Influenza (HPAI) as of November 2022 (Tremlett et al, 2024).

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