BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Anas discors | Blue-Winged Teal 



TIMING OF MAJOR LIFE HISTORY EVENTS : 
Courtship and pair bonding - The onset of courtship among immature
blue-winged teal often starts in late January or early February.  In
areas south of the breeding grounds, blue-winged teal are more active in
courtship during the spring migration than are most other ducks [1].

Nesting - Blue-winged teal are among the last dabbling ducks to nest
[1], generally nesting between April 15 and May 15 [1,2].  Few nests are
started after mid-July [1].  Chronology of nesting can vary from year to
year as a result of weather conditions.  At Delta Marshes, Manitoba,
blue-winged teal nesting was delayed a week in 1950 due to abnormally
cold weather [1].

Clutch/incubation - Blue-winged teal generally lay 10 to 12 eggs [10].
Delayed nesting and renesting efforts have substantially smaller
clutches, averaging five to six eggs [10].  Clutch size can also vary
with the age of the hen.  Yearlings tend to lay smaller clutches [1].
Incubation takes 21 to 27 days [1,2,10].

Age at sexual maturity - Blue-winged teal are sexually mature after
their first winter [10].

Fledging - Blue-winged teal ducklings can walk to water within 12 hours
after hatching but do not fledge until 6 to 7 weeks [2,10].

Molting - During incubation, the drake leaves its mate and moves to
suitable molting cover where it becomes flightless for a period of 3 to
4 weeks [10].

Migration - Blue-winged teal are generally the first ducks south in the
fall and the last ones north in the spring [1].  Adult drakes depart the
breeding grounds well before adult hens and immatures.  Most blue-winged
teal flocks seen after mid-September are composed largely of adult hens
and immatures [1].

The northern regions experience a steady decline in blue-winged teal
populations from early September until early November.  Blue-winged teal
in central migration areas tend to remain through September, then
diminish rapidly during October, with small numbers remaining until
December.  Large numbers of blue-winged teal appear on wintering grounds
in Florida, Louisiana, and Texas in September [1].


PREFERRED HABITAT : 
Breeding habitat - Blue-winged teal inhabit shoreline more often than
open water and prefer calm water or sluggish currents to fast water.
They inhabit inland marshes, lakes, ponds, pools, and shallow streams
with dense emergent vegetation [4].  In coastal areas, breeding occurs
in salt-marsh meadows with adjoining ponds or creeks [10].  Blue-winged
teal use rocks protruding above water, muskrat houses, trunks or limbs
of fallen trees, bare stretches of shoreline, or mud flats for resting
sites [4].

Winter habitat - Blue-winged teal winter on shallow inland freshwater
marshes and brackish and saltwater marshes [4].

Nesting habitat - Blue-winged teal build their nests on dry ground in
grassy sites such as bluegrass meadows, hayfields, and sedge meadows.
They will also nest in areas with very short, sparse vegetation [6].
Blue-winged teal generally nest within several hundred yards of open
water; however, nests have been found as far as 1 mile (1.6 km) away
from water [1].  Where the habitat is good, they nest communally [4].


COVER REQUIREMENTS : 
Blue-winged teal often use heavy growth of bulrushes and cattails as
escape cover [2].  Grasses, sedges, and hayfields provide nesting cover
for these ducks [6].  Fritzell [6] reported that blue-winged teal nests
located in light to sparse cover were more successful than those in
heavy cover.  Nesting success was 47 percent on grazed areas and 14
percent on ungrazed areas [6].


FOOD HABITS : 
Blue-winged teal are surface feeders and prefer to feed on mud flats, in
fields, or in shallow water where there is floating and shallowly
submerged vegetation plus abundant small aquatic animal life.  They
mostly eat vegetative matter consisting of seeds or stems and leaves of
sedge, grass, pondweed, smartweed (Polygonum spp.), duckweed (Lemna
spp.), widgeongrass, and muskgrass (Chara spp.) [1,4,10].  The seeds of
plants that grow on mud flats, such as nutgrass (Cyperus spp.),
smartweed, millet (Panicum spp.), and rice cut-grass (Leersia
oryzoides), are avidly consumed by this duck [1].  One-fourth of the
food consumed by blue-winged teals is animal matter such as mollusks,
crustaceans, and insects [1,4,10].


PREDATORS : 
Common predators of blue-winged teal include humans, snakes, snapping
turtles (Chlycha serpentina), dogs (Canidae), eastern crows (Corvus
brachyrhnchos), magpies (Pica spp.), ground squirrels (Citellus spp.),
coyotes (Canis latrans), red foxes (Vulpes fulva), gray foxes (Urocyon
cinereoargenteus), raccoons (Procyon lotor), long-tailed weasels
(Mustela frenata), minks (Mustela vison), striped skunk (Mephitis
mephitis), spotted skunks (Spilogale putorius), and badgers (Taxidea
taxus) [1,2].

During one study, about half of the nest failures of blue-winged teal
were caused by mammals.  Striped and spotted skunks were responsible for
two-thirds of these losses.  All nest losses caused by birds were
attributed to either crows or magpies [1].


MANAGEMENT CONSIDERATIONS : 
Farm activities such as mowing of hayfields, plowing, fence-building,
and trampling by cattle can destroy blue-winged teal nests [1].

In spite of low hunting losses, blue-winged teals have a higher annual
mortality than other dabbling ducks.  Perhaps the high nonhunting losses
occur because of the blue-winged teal's lengthy overwater flights to
South America [1].


REFERENCES : 
NO-ENTRY

Related categories for Wildlife Species: Anas discors | Blue-Winged Teal