# Sandwich Tern

Scientific name: Thalasseus sandvicensis

Bird group: [gull](https://birdsofpuertorico.com/family/gull)

Canonical source: https://birdsofpuertorico.com/bird/136/Sandwich-Tern

## Identification

The Sandwich tern (Thalasseus sandvicensis) is a tern in the family Laridae. It is very closely related to the lesser crested tern (T. bengalensis), Chinese crested tern (T. bernsteini), Cabot's tern (T. acuflavidus), and elegant tern (T. elegans) and has been known to interbreed with the lesser crested. It breeds in the Palearctic from Europe to the Caspian Sea wintering to South Africa, India and Sri Lanka.


## Distribution and habitat

The Sandwich Tern occurs through the tropical, subtropical, 
and temperate coastal regions 
of the Atlantic Ocean (Raffaele 
and others 1998). In Puerto Rico, 
it can be seen throughout the 
year, but it is most abundant 
from September to November 
and from March to May (Biaggi 
1997). It nests on and around 
Culebra and some islets off 
Guayanilla and La Parguera in 
the municipality of Lajas, while 
it is a regular visitor during the 
winter in the San Juan harbor 
and the bays of Boquerón and 
Mayagüez (Kepler and Kepler 
1978, Oberle 2018). It is also present on Vieques, where it 
is considered a rare visitor in 
summer and fall, and extremely 
rare in spring (Gemmill 2015). 
It usually inhabits coastal areas, 
harbors, and lagoons (Raffaele 
and others 1998). The atlas 
fieldwork yielded a total of 76 
records within 55 hexagons or 11 
percent of the 479 total hexagons 
(see map). Of the 55 hexagons 
where this species was found, 
breeding met the atlas definition 
of confirmed in 5 percent (3) of 
the hexagons, while this species 
was observed in 95 percent (52) 
of the hexagons but without 
evidence of breeding (see map).Sandwich Tern distribution. The map shows the highest breeding code by hexagon and overlaying the ecological life zones in 
Puerto Rico. Note: percentages may not total 100 due to rounding.       127Sandwich Tern/Charrán Piquiagudo

## Breeding

Previously published reports indicate that the Sandwich Tern 
breeds from May to July (Raffaele 
and others 1998). A simple 
scrape nest is made on a sand 
bar or in coral rubble (Raffaele 
and others 1998). Atlas results 
confirm that this species breeds 
in June and that the breeding 
activity takes place in the 
subtropical dry forest life zone 
(see chart). Results show that this species breeds in coastal areas 
within the subtropical dry forest 
life zone (100 percent of the 
hexagons) (see table and map).

## Conservation

The current overall population trend of the Sandwich Tern is 
fl uctuating, although some of 
the populations are stable and 
others have unknown trends 
(Wetlands International 2012). 
This species is currently listed as a species of least concern by 
the IUCN (BirdLife International 
2018). Locally, this species is not 
listed in any of the threatened 
categories of PRDNER and 
USFWS. In Puerto Rico, the 
Sandwich Tern has a protected 
habitat in land of 3 percent or 2 
km2 of the total area covered by the hexagons where evidence 
of breeding was found for this 
species (72 km2).

Photo: https://birdsofpuertorico.com/static/images/webp/in_136_Im0.png.webp

Distribution map: https://birdsofpuertorico.com/static/images/webp/in_136_Im1.png.webp

Source note: Text is reproduced from this site's published record. Historical conservation statements and taxonomy have not been independently revalidated. See https://birdsofpuertorico.com/about for source credits and limitations.