Pine Siskin - Spinus pinus

Pine Siskin has a partial preformative molt and limited prealternate molts. Age can generally be determined by the presence (first cycle - HY/SY) or absence (definitive cycle - AHY/ASY) of molt limits among the median and greater coverts, but note that feather differences by age can be subtle in this species. Sex is generally not determined reliably by plumage, although the yellow patches on the primaries and secondaries tend to be larger and brighter on males, especially among definitive cycle birds (AHY/ASY).

Quick tips

• Examine the median coverts and greater coverts - on FCF/FCU (HY/SY) individuals there is a subtle contrast between darker replaced inner feathers with pale to white tips versus slightly paler outer feathers with buff tips; note that some individuals replace all greater coverts in their preformative molt, such that the contrast is between the greater and primary coverts; on DCB/DCU (AHY/ASY) the coverts are uniform in appearance.
• Examine the outer rectrices, which are relatively broad and rounded on DCB/DCU (AHY/ASY) birds and tend to be somewhat narrower and more pointed on FCF/FCU (HY/SY) birds, though intermediates can be difficult to assess; extensive yellow patches on the rectrices are likely indicative of DCB/DCU (AHY/ASY) males.
• Examine the primary coverts, which tend to be tapered and dull on FCF/FCU (HY/SY) birds, and more rounded with distinct yellowish edging on DCB/DCU (AHY/ASY) birds.
• Look at the extent of yellow on the primaries extending beyond the primary coverts - the length typically ranges from several mm on DCB/DCU (AHY/ASY) males to largely absent on FCF/FCU (HY/SY) birds, with DCB/DCU (AHY/ASY) females intermediate and unreliably separated by this characteristic.

Species account prepared by McGill Bird Observatory (2018). Last updated by Marcel Gahbauer (Mar 2022)