# Least Bittern

Scientific name: Ixobrychus exilis

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

Canonical source: https://birdsofpuertorico.com/bird/154/Least-Bittern

## Identification

The least bittern (Ixobrychus exilis) is a small heron, the smallest member of the family Ardeidae found in the Americas.


## Distribution and habitat

The Least Bittern occurs from North America through Central 
and South America including the 
West Indies (Raffaele and others 
1998), where it is an uncommon 
to locally common resident in 
Puerto Rico (J.A. Salguero-Faría, 
personal observation 2009). It is 
regularly seen at the Humacao 
Natural Reserve (Oberle 2018). 
It is present on Vieques, where 
it ranges from rare to extremely 
rare (Gemmill 2015), and is also 
present on Culebra. It usually 
inhabits shallow marshes, pond 
edges, mangroves (Oberle 2018), and freshwater swamps with 
dense emergent vegetation, often 
cattails (Typha spp.) (Raffaele 
and others 1998). The atlas 
fieldwork yielded a total of 44 
records within 29 hexagons or 6 
percent of the 479 total hexagons 
(see map). Of the 29 hexagons 
where this species was found, 
breeding met the atlas definition 
of confirmed in 24 percent (7) 
of the hexagons, probable in 7 
percent (2), and possible in 62 
percent (18), while the species 
was observed in 7 percent (2) 
of the hexagons but without 
evidence of breeding (see map).Least Bittern 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.       145Least Bittern/Martinetito

## Breeding

Previously published reports indicate that the Least Bittern 
breeds from May to August 
(Raffaele and others 1998). 
The nest is usually constructed 
above standing water on aquatic 
vegetation, and it is made mostly 
of twigs, weeds, cattails, and 
other swamp plants (Biaggi 1997, 
Raffaele and others 1998). Atlas 
results suggest that this species 
breeds mostly from December 
to August with peak breeding 
activity in February, March, and 
May (see chart). The breeding activity mostly takes place within 
the subtropical moist forest life 
zone (see chart). Results (see 
table and map) show that this 
species breeds mostly on the 
coastal plain or lowlands within 
the subtropical moist forest 
life zone (74 percent of the 
hexagons) with some evidence 
for breeding found in the 
subtropical dry forest life zone 
(26 percent of the hexagons).

## Conservation

The current population trend of the Least Bittern is described as stable (Butcher and Niven 
2007). This species is currently 
listed as a species of least 
concern by the IUCN (BirdLife 
International 2016). Locally, this 
species is not listed in any of the 
threatened categories of PRDNER 
and USFWS. In Puerto Rico, the 
Least Bittern has a protected 
habitat in land of 14 percent or 
91 km2 of the total area covered by the hexagons where evidence 
of breeding was found for this 
species (645 km2).

Photo: https://birdsofpuertorico.com/static/images/webp/in_154_Im0.png.webp

Distribution map: https://birdsofpuertorico.com/static/images/webp/in_154_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.