Difference Bwteen Dark Eyed Junco and Blue Gray Gnatcatcher
Dark-eyed Junco - Junco hyemalis
Dark-eyed Junco has a partial preformative molt, and limited prealternate molts that are largely restricted to feathers on the head. Although the preformative molt often results in distinct molt limits, these can sometimes be subtle, so caution is advised for those that appear to be DCB/DCU (AHY/ASY). Plumage can often be used to determine sex, but beware that there is a gradient of colouration, and that FCF/FCU (HY/SY) males and DCB/DCU (AHY/ASY) females can appear quite similar.
There are several subspecies of Dark-eyed Junco in North America; the descriptions provided are based largely on Slate-colored Junco, but are believed to be broadly applicable to the other subspecies as well.
Quick tips
- Examine the greater coverts - FCF/FCU (HY/SY) birds often have a conspicuous molt limit among the greater coverts with retained brown outer coverts contrasting with replaced gray inner coverts, while DCB/DCU (AHY/ASY) birds have uniform greater coverts.
- Look at the back and head - DCB/DCU (AHY/ASY) males are dark gray with little or no brown, FCF/FCU (HY/SY) males and DCB/DCU (AHY/ASY) females are medium gray with brown especially on the back, and FCF/FCU (HY/SY) females are brownish-gray and paler than other ages/sexes.
- Check the tail - on FCF/FCU (HY/SY) birds the outer rectrices are narrow and tapered, while on DCB/DCU (AHY/ASY) birds they are broad and rounded; note that the amount of white does not appear to reliably correspond to age or sex.
- In fall and winter, look at the iris under good light - it is grayish-brown on FCF/FCU (HY/SY) birds, and reddish-brown on DCB/DCU (AHY/ASY) birds.
Species account prepared by McGill Bird Observatory (2016). Last updated by Marcel Gahbauer (Mar 2022)
- Reference (8)
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The molt categories displayed below may be filtered by month.
Click on any image below to bring up the side-by-side comparison tool.
Individuals not in molt
| FCJ - (HY: May - September) | |||
|---|---|---|---|
| Mottled head and finely streaked underparts | |||
| No images available yet | |||
| FCF - (HY: July - December; SY January - March) | |||
| Rectrices narrow and pointed; distinct molt limit either within greater coverts or between greater and primary coverts; iris grayish-brown; upperparts dark gray with some brown (M) or mostly brown with some gray (F) | |||
| M | | ||
| F |
| ||
| FCU - (SY: March - September) | |||
| Rectrices narrow and pointed; distinct molt limit either within greater coverts or between greater and primary coverts; iris brown to reddish-brown; upperparts dark gray with some brown (M) or mostly brown with some gray (F) | |||
| M | | ||
| DCB - (AHY: July - December; ASY January - March) | |||
| Rectrices fairly broad and rounded; colour and condition of greater coverts and primary coverts fairly uniform; iris reddish-brown; upperparts dark gray (M) or a mix of gray and brown (F) | |||
| M | | ||
| F | | ||
| DCU - (ASY: March - September) | |||
| Rectrices fairly broad and rounded; colour and condition of greater coverts and primary coverts fairly uniform; iris reddish-brown; upperparts dark gray (M) or a mix of gray and brown (F) | |||
| M | | ||
| F | | ||
Individuals in active molt
| FPJ - (HY: May - September) | |
|---|---|
| Mottled head and finely streaked underparts; some natal down remaining and/or juvenile flight feathers still growing in | |
| No images available yet | |
| FPF - (HY: July - October) | |
| Similar to FCF; median and some to all greater coverts and in rare cases also tertials and central rectrices being replaced | |
| No images available yet | |
| FPA - (SY: February - April) | |
| Similar to FCF, with some replacement of head and other body feathers | |
| No images available yet | |
| SPB - (SY: July - October) | |
| Flight feathers being replaced, with retained juvenile primaries, secondaries, and/or primary coverts distinctly brown and very worn | |
| No images available yet | |
| DPB - (AHY: July - October) | |
| Flight feathers being replaced, with retained primaries, secondaries, and/or primary coverts either distinctly adult (more gray than brown, less worn) or intermediate | |
| No images available yet | |
| DPA - (ASY: February - April) | |
| Similar to DCB, with some replacement of head and other body feathers | |
| No images available yet |
Applicable unknown plumage/age classes
| Molt classes | Age | Months | Key traits |
|---|---|---|---|
| M-FPF / UPU (FPF, SPB, DPB) | U | July - October | Undergoing preformative or prebasic molt, but cycle is not reliably distinguishable |
| M-FCF / UCU (FCF, SCB, DCB) | U/AHY | July - March | In formative or basic plumage (molt completed), but cycle is not reliably distinguishable |
| M-FPA / UPA (FPA, DPA) | AHY | February - April | Undergoing prealternate molt, but cycle is not reliably distinguishable |
| M-FCA / UCA (FCA, DCA) | AHY | March - September | In alternate plumage (molt completed), but cycle is not reliably distinguishable |
Source: https://www.natureinstruct.org/piranga/browse?projectId=3&id=05FF3C9B3C854D53
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