Red-winged Blackbird

Agelaius phoeniceus

Introduction

The Red-winged Blackbird is perhaps the most abundant and most commonly studied bird of North America. Although this Blackbird varies in size geographically, adults of all populations are sexually dimorphic in size, plumage, and behaviour. The male is larger, possesses the more conspicuous definitive adult plumage, and is more conspicuous in his behaviour than is the female.
The Red-winged Blackbird breeds in marsh and upland habitats from southern Alaska and central Canada to Costa Rica, and from California to the Atlantic Coast and West Indies. This blackbird migrates to and from the northern portions of its breeding range, but some populations in the western United States and Gulf Coast are known to be resident year-round, as are populations in Middle America.

Identification

Adult Male (spring/summer)

Male displays delayed plumage maturation; third-year and older male is glossy black with “epaulets” of red (for which species is named) bordered with yellow on wrist (bend) of wing. Second-year male is highly variable in plumage, from female-like brown with heavily streaked breast to black with brown flecks; epaulets are also variable, typically red-orange with brown or black spotting.

Adult Female (spring/summer)

Females also show some delayed plumage maturation, but less than male. All females are mottled brown above and heavily streaked below with a prominent white eyebrow stripe. Third-year and older females are variable in throat (pink to buffy) and epaulet (dull orange to bright red-orange) colour. Second-year females are less variable, throat and face light pink, epaulets brown to salmon.

Juvenile

Similar to adult female, but darker and with an orangish shoulder patch bordered by white.

General Information

General:

Stocky, broad shouldered Blackbird. Length: 17-23cm. Wing: 31-40cm Weight: 32-77grams.

Behaviour:

Known especially for feeding by gaping, i.e. forcibly opening bill against resistance. Uses gaping to expose insects hiding in the sheathing of leaf bases of aquatic plants, under sticks, seeds, or other objects on the ground or on floating vegetation, and under stones in stream riffles. Also captures food simply by picking up seeds and other items from ground and buy gleaning insects from vegetation.
Red-wings form the nucleus of huge flocks of mixed blackbird species that feed in fields, pastures, and marshes from early fall to spring.

Habitat:

Breeds in a variety of wetland and upland habitats. Wetland habitats include freshwater marsh, saltwater marsh, sloughs or where bushes and small trees grow in and around ponds, lakes, and sluggish streams. Upland breeding habitats commonly include sedge meadows, alfalfa fields and other croplands, and old fields; less commonly in wooded areas along waterways and in open patches in woodlands.

Information:

The Red-winged Blackbird is known for its polygynous social system. Up to 15 females have been observed nesting on the territory of a single male, making this one of the most highly polygynous of all bird species. Recent molecular studies have shown that territory owners do not necessarily sire all of the nestlings on their territories, which demonstrates that females as well as males often copulate with more than one partner during a breeding season and even for a single nesting attempt.
The nest is situated in cattails, rushes, bushes, trees sometimes over water, in alfalfa and other plants of upland fields, even on the ground in dense grass.
It is a loosely woven cup of dried cattail leaves, sedges, fastened to plants or twigs with plant fibers, cup lined with fine grasses, rushes. The clutch is 3-5 pale blue-green, heavily marked eggs.

Similar species:

Brewer’s Blackbird, Brown-headed Cowbird, Common Grackle, European Starling, Song Sparrow.

Conservation Status:

Listed as Least Concern.

Maps & Statistics

Capture Rates:

Some populations of Red-winged Blackbirds are year round residents of the Lower Mainland while other populations move short distances south for the winter. Capture rates of this species occur in almost every month of the year in good numbers. However, numbers especially peak in February due to the influx of non-resident birds returning to their breeding grounds.

Ageing and Sexing (Band Size: M: 2 / F: 1A)

Molt Summary:

PF: HY incomplete-complete; PB: AHY complete; PA SY limited-partial, ASY absent-limited.
Preformative molt includes all flight feathers, except that occasionally 1 – 5 middle ss (among s1 – s6) can be retained, and all body plumage, except possibly some to most gr underwing covs.
The PA’s include some or all body feathers but no gr covs or flight feathers.

Juvenile

MAY - SEPTEMBER

Juveniles are similar to HY/SY females but paler and buffier overall – measurements are reliable for sexing as females are considerably smaller requiring a smaller band size.

Wing chord (sexing):
Female: <110mm Male: >110mm

The two HY females in June and July below are showing very buffy faces and have the other characteristics of birds in juvenal plumage (e.g. prominent gapes and loosely textured feathers – note the natal plumes on the hindcrown in the top photo (red arrow).

HY/SY females not in juvenal plumage show black, brown and buffy streaked body plumage and blackish lesser coverts with buffy orange tips.

HY/SY

AUGUST - July

The last juvenal feathers to be replaced of blackbirds and cowbirds are found among the underwing coverts. The contrasts between retained juvenal and basic underwing coverts of males are obvious but contrasts between juvenal and basic underwing coverts in females of these species are much more difficult to discern; furthermore, depending on the species and/or populations being studied, the absence of any retained juvenal underwing coverts may or may not be confidently interpreted as evidence that the bird is an ASY individual.

The underwing coverts of this HY male in September are showing molt limits in the making between retained feathers and replaced feathers still in sheath (red arrows).

This HY female in September is in the midst if its preformative molt replacing primaries and secondaries together with wing coverts. Notice the difference in rachis colour between the retained and replaced feathers and molt limit between the greater alula covert (A1) in sheath and the as-yet unmolted lower main alula feathers (red arrow).

This HY male in August is replacing worn, lightly pigmented brownish juvenal feathers with pale brown rachises with glossy black, truncate feathers with black rachises. Notice also the replaced orangish lesser coverts of this HY bird which will be replaced by bright red feathers in the birds first definitive adult prebasic molt following the breeding season next year.

A similar example of a HY male in September replacing worn, lightly pigmented brownish juvenal feathers with pale brown rachises with glossy black, truncate feathers with black rachises. Notice again the replaced orangish lesser coverts of this HY bird which will be replaced by bright red feathers in the birds first definitive adult prebasic molt following the breeding season next year.

The contrast between retained and replaced underwing coverts in females is often much more difficult to see. This SY female in April is showing a strong contrast between retained and replaced underwing coverts (indicated by the red arrow pointing to replaced feathers and blue arrow pointing to retained feathers).

Second year males like this SY in May are much duller than ASY males with lesser coverts which are dull orangish or orangey red and yellow mixed with blackish feathers.

A close up of the orangey red mixed with blackish lesser coverts of a second year male are shown in the macro photo below. SY males do not have the bright red lesser coverts of adult (ASY) males shown below.

Underwing coverts are often retained in the preformative molt contrasting markedly with the adjacent blacker feathers in males. The 4 photos immediately below show the retained and replaced underwing coverts of SY males (red arrows pointing to replaced feathers).

Although the preformative molt can include all flight feathers, often some remiges (primaries and secondaries) are retained. This SY male in February is showing a very obvious contrast between retained and replaced feathers. Notice the difference in rachis colour between the retained and replaced feathers and orangey red mixed with extensive black lesser coverts.

This SY male in February is showing an extensive incomplete preformative molt having replaced most wing feathers but notice again the orangey red mixed with blackish lesser coverts.

AHY/ASY

AUGUST - July

Adult (AHY/ASY) males have uniformly glossy black body plumage often with extensive rusty feather edging and bright scarlet red lesser coverts.

This super-macro shot showing the lesser and median coverts shows the uniformly, bright red lesser coverts with no blackish mottling of adult males compared to the first year (HY/SY) males above.

The underwing coverts of adult (AHY/ASY) males like this ASY in May are glossy blackish with little or no contrast between adjacent feathers.

As the preformative molt can include all flight feathers tail shape is not helpful in ageing this species. The tail of this ASY male in February is already showing extensive wear to the tips.

AHY females like this bird in February have body plumage similar to HY/SY females but generally with brighter rusty-orangish to reddish lesser coverts forming indistinct epaulettes. The chin is also washed with peach or pinkish.

Females are altogether more difficult to age not having the contrasting glossy black plumage of their male counterparts. Although underwing coverts can be retained in second year birds they are extremely difficult to see even under magnification often leading to safer age determinations of after hatch year (AHY) in winter and spring.

The lesser coverts of adult females like this bird in February normally show mixed bright orange and blackish feathers forming an indistinct shoulder patch or epaulette. This bird was therefore aged as an AHY female but noted as ‘leaning towards ASY’ or after second year in our notes.

Again, as the preformative molt can include all flight feathers tail shape is not helpful in ageing this species. The tail of this AHY female in February is showing very fresh rectrices with virtually no wear to the tips.