American Goldfinch

American Goldfinches are members of the Fringillidae and are very common across temperate North America. They have a striking bright yellow appearance and are the only cardueline finches that attain their breeding plumage by moulting. In addition, they are among the latest breeders of all temperate passerines in North America, which may be linked to their unusual moulting habits. The northern limit of their breeding range stretches from the south-western portion of Newfoundland across Canada to western British Columbia. The southern limit extends from the coast of North Carolina across the United States to North California. American Goldfinches shift southward during the winter season, although their breeding and wintering ranges overlap. The northern limit of their winter range extends from southern Nova Scotia, across eastern Canada and the northern United States to southern British Columbia. The southern limit reaches from Florida to Mexico and then extends westward to California.

Adult Male (spring/summer)
During the breeding season males appear bright yellow with black caps, black wings, yellow shoulder patches and white bars, white uppertail/undertail coverts, black and white tail.

Adult Female (spring/summer)
During the breeding season, females are yellow-brown with white undertail coverts. Females lack black cap and yellow shoulder patch.

Adult Male (fall/winter)
During the non-breeding season, males are brownish/greyish and may have black foreheads.

Adult Female (fall/winter)
During the non-breeding season, the colours of the females are subdued.

General:

American Goldfinches are relatively small birds with conical bills and notched tails. Length: 12.5-13cm. Wing; 23cm. Weight: 13grams.

Juvenile:

Juveniles have a brownish appearance with cinnamon buff wing markings and rump.

Behaviour:

Although American Goldfinches often avoid settling the ground, occasionally they can be seen hopping along the ground surface. They will often engage in water bathing and presumably in sun and dust bathing. American Goldfinches are social birds and are often observed in the company of others..

Habitat:

American Goldfinches can be found in a range of open habitats including orchards, overgrown fields, roadsides, hedgerows, river flood plains and second growth forests.

Information:

American Goldfinches feed throughout the day and perch while feeding on small seeds of plants and trees. During the non-breeding season, they are often observed feeding in large flocks and may be accompanied by chickadees, redpolls and sparrows.

The main cause of nest failure and mortality during breeding season is predation; however, mortality during the winter season is much higher and is usually related to the physiological state of the birds. Prolonged and frequent winter storms may decrease food availability, increase physiological stress and lead to starvation.

The maximum lifespan for American Goldfinches is approximately 11 years, although males usually live longer than females.

Typical clutch size for American Goldfinches is 5 eggs per nest but is related to female age. Older females usually lay larger clutches and raise more young than do less experienced females. Depending on habitat type, nest success ranges from 31 to 66 percent.

Similar species: ​

Wilson’s Warbler, Lesser Goldfinch, Lawrence’s Goldfinch, Evening Grosbeak.
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Conservation Status:

Least Concern

Despite the introduction of new predators such as cats, American Goldfinches appear to have benefitted from European settlement. The introduction of agriculture has increased the amount of available nesting habitat and food availability in breeding and winter seasons. The Breeding Bird Survey of Canada indicates that despite their high abundance, populations have decreased in central and eastern Canada (1981-1995). Similar results are reported by the Breeding Bird Survey of the United States who observed declines in most western states; declines may be due to conversion of farmland and the expansion of urban centers. Given their large abundance and distribution, American Goldfinches are not under threat; however, they have responded positively to restoration efforts of savannah habitats in Midwestern United States.

Capture Rates

Capture rates of American Goldfinch peak in spring (April-May) and early fall (August). American Goldfinch move south in winter to regions where the minimum temperature remains above 0 degree Fahrenheit.

Molt Summary:

PF: HY partial, PB: AHY complete; PA partial (Feb-Jul)
PF includes most or all al med covs, 4 – 10 inner gr covs and occasionally s8 but no rects.
1st PA includes 0 – 6 inner gr covs and occasionally s8 but no terts or rects.

In alternate plumage, both age classes of American Goldfinch (AMGO); second year (SY) and after second year (ASY) have very bright body plumage and soft part (e.g., bill) coloration, but SY birds typically have dull greenish brown epaulets (lesser coverts) at the bend of the wing.

ASY birds usually have bright yellow ‘shoulders’ although this criterion alone is not altogether reliable for determining age of AMGO males, because ASY males sometimes have dull greenish lesser coverts, and SY birds sometimes will show precocious development of bright yellow lesser coverts.

Ageing American Goldfinches is easier than in many species as there are two ageing shortcuts banders can use. First we look for a buffy tip on the carpal covert. Only first year (HY/SY) birds have a buffy fringe to the terminal edge of this feather – adults lack this buffy tip to the carpal covert (although they can show a white tip) and in spring/summer AMGO’s are the ONLY birds where we can use the prealternate molt for ageing as only SY birds molt their inner GC’s as part of their prealternate molt.

Ageing and Sexing American Goldfinch (Link)

Our good friend and molt expert extraordinaire Bob Mulvihill wrote a comprehensive blog post during his time at the Powdermill Avian Research Center which can be viewed by clicking the link above.

 

Juveniles are brownish yellow, often with streaks in the upperparts, and have buffy brown wingbars. Most juveniles can be sexed by the colour of the flight feathers and amount of white in then outer rects (r6).

This SY male in May is showing the buffy fringe to the carpal covert (red arrow) and dull greenish lesser coverts (black arrow).

Note also the glossy, black inner greater coverts (blue arrow) replaced during the late winter/early spring as part of its prealternate molt.

A macro shot of the buffy tipped carpal covert, greater alula covert and lower alula feathers and buffy fringes to the under alula coverts of an SY male in May.

A close up of replaced inner greater coverts (blue arrow) of an SY male in May showing the glossy black feathers replaced during the birds prealternate molt in the late winter / early spring. Notice the difference in gloss, sheen and wear between the replaced and retained feathers.

This SY female in May is again showing the buffy fringe to the carpal covert (red arrow) and replaced inner greater coverts (blue arrow) from its prealternate molt in late winter / early spring.
Note also the brownish not blackish remiges (primaries and secondaries) of females versus males above.

This close up of the coverts of an SY female in May is again showing the buffy tip to the carpal covert which can also often be seen extending to the greater alula covert (A1) and lower main alula feathers (red arrows) and glossier replaced inner greater coverts and median coverts (blue arrows) as part of the prealternate molt in the late winter/early spring.

Contrast the above with this ASY male in April showing bright yellow lesser coverts and a completely black carpal covert with no contrasting edging to the terminal edge of this feather (red arrow).

Note that adults like this ASY male in April may show a whitish tip to the carpal covert (red arrow) but never the buffy fringe shown in first year (HY/SY) birds.

Tail shape is also a helpful ageing and sexing criteria for this species, the outer rectrix (R6) more rounded, relatively fresh, and black with a distinct, white patch in adult males like this ASY male in June versus tapered, more worn with a less distinct, white patch in first year birds and generally less extensive white patch in adult females.

This ASY female in May is showing uniformly adult wing coverts not contrasting markedly in colour or wear between the feather groups. Notice the brownish remiges (primaries and secondaries) of the female versus male above, the lack of replaced inner greater coverts and carpal covert lacking the buffy fringe of first year (HY/SY) birds.

The final photo below shows how the molt and plumage criteria explained above can be used to age birds more accurately even when they are in heavy flight feather molt. Here we have an SY male at the start of its first definitive adult prebasic molt in August. We have seen above how in spring SY birds show three generations of feathers; juvenal, formative and first alternate but in this photo we can now see FOUR generations of feathers: Yellow arrows: Retained juvenal feathers (outer primaries P4-P9 and corresponding primary coverts, outer secondaries S1-S6, outer greater coverts carpal covert and alula, the red arrows pointing to the buffy fringes on the retained juvenal carpal covert and alula mentioned earlier).

Purple arrow: Formative inner greater coverts replaced during the birds preformative molt after the breeding season last year.

Blue arrow: First alternate inner greater coverts replaced during the birds first prealternate molt during the late winter/early spring.

Green arrows: Adult prebasic inner primaries (P1-P3), corresponding primary coverts and tertials being replaced as part of the birds adult prebasic molt now.