Pied-billed Grebe
Description
The pied-billed grebe (Podilymbus podiceps) is a species of the grebe family of water birds. Because the Atitlán grebe (Podilymbus gigas) has become extinct, the Pied-Billed Grebe is now the sole extant member of the genus Podilymbus. The pied-billed grebe is primarily found in ponds throughout the Americas. Other names of this grebe include American dabchick, rail, dabchick, Carolina grebe, devil-diver, dive-dapper, dipper, hell-diver, pied-billed dabchick, pied-bill, thick-billed grebe, and water witch.
Pied-billed grebes are small, stocky, and short-necked. They are 31–38 cm (12–15 in) in length, with a wingspan of 45–62 cm (18–24 in) and weigh 253–568 g (8.9–20.0 oz).[10] They are mainly brown, with a darker crown and back.[11] Their brown color serves as camouflage in the marshes they live in.[12] They do not have white visible under their wings when flying, like other grebes.[13] Their undertail is white[11] and they have a short, blunt chicken-like bill that is a light grey color,[11] which in summer is encircled by a broad black band (hence the name). In the summer, its throat is black. There is no sexual dimorphism.[13] Juveniles have black and white stripes and look more like winter adults. This grebe does not have webbed feet. Its toes have lobes that come out of the side of each toe. These lobes allow for easy paddling. When flying, the feet appear behind the body due to the feet's placement in the far back of the body.[11]
Threats
They are extremely sensitive to disturbances, especially by humans. While breeding, if scared, adults may abandon their nests without protecting the eggs. The waves from boats can destroy the nests and their sounds easily frighten the birds.[12]
Distribution & Habitat
The Pied-billed Grebe occurs throughout the Western
Hemisphere including the West
Indies (Raffaele and others 1998).
In Puerto Rico, the species is a
common resident in wetlands,
ponds, and reservoirs in the
coastal plain and lowlands
(Oberle 2018). It also occurs on
Culebra and Vieques (PRDNER
2015, Saliva 1994, Sorrié 1975,
Ventosa-Febles and others 2005),
in the latter being a rare resident
(Gemmill 2015). The atlas
fieldwork yielded a total of 157
records within 89 hexagons or 18
percent of the 479 total hexagons
(see map). Of the 89 hexagons
where this species occurs, breeding met the atlas definition
of confirmed in 28 percent (25)
of the hexagons, probable in 16
percent (14), and possible in 56
percent (50) (see map).
Breeding Habits
The Pied-billed Grebe builds a fl oating nest among emergent
vegetation (Raffaele and others
1998). Previously published
reports indicate that it breeds
throughout the year, but mostly
from March to July (Raffaele
and others 1998). Atlas results
show that this species breeding
season extends throughout the
year with most breeding activity
from March to June (see chart). Pied-billed Grebe 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. 39Pied-billed Grebe/ZaramagoThe breeding activity peaks during March and June, and it
mostly takes place within the
subtropical moist forest life
zone (see chart). Results show
that this species breeds mostly
within the subtropical moist
forest life zone (74 percent of the
hexagons) throughout the island.
However, results indicate that it
also breeds in the subtropical dry
forest life zone (20 percent of
the hexagons), and subtropical wet and lower montane wet
forest life zones (6 percent of the
hexagons) (see table and map).
Conservation
The current population trend of the Pied-billed Grebe is
described as stable, although
some populations have unknown
trends (Wetlands International
2012). 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
Pied-billed Grebe has a protected
habitat in land of 12 percent or
253 km2 of the total area covered by the hexagons where evidence
of breeding was found for this
species (2127 km2).
Related Species
Family:
grebe