1. In Hand Ageing and Sexing Techniques:
Molt Pattern Shortcuts and Summaries
Adrienne J. Leppold and Robert S. Mulvihill

2. North American Bird Bander Vol. 18 No. 1
A great reference, summarizes the information in this presentation and more
North American Bird Bander Vol. 18 No. 1

3. The molt patterns summarized here are general for each of the families mentioned. Different geographic races of species, especially western birds, may have a more or less extensive molt depending on the individual, where it is from, and where your banding site is located.

4. Summaries of Molt Patterns for Passerines (and some near passerines)
- Know Where to Look
Consistencies within genera and families of birds
Correctly sexing a bird, more often than not, depends on correctly ageing it first. Always remember that immature (HY/SY) males can look a lot like adult (AHY/ASY) females.
- Ageing shortcuts

5. Black-throated Blue Warbler
CC/A1 Molt Limits
Parulids
CC= carpal covert/A1 = greater alula covert (top feather, smallest of the three) This photo shows an A1 molt limit (red arrow), note the obvious difference between A1 and A2 in this case. The difference in feathers is defined by multiple qualities though. Look beyond color and assess wear, sheen, gloss, and shaft color. Feather shape should be used with caution as it is not a consistent or reliable characterisitc
Black-throated Blue Warbler

6. Parulids CC/A1 Molt Limits Northern Parula Cerulean Warbler
These two photos show CC molt limits, the upper left is “a molt limit in the making.” You may also notice that the bird in the lower right hand corner abnormally retained the two outer GC (Greater Coverts)
Cerulean Warbler

7. CC/A1 Molt Limits Parulids American Redstart
CC molt limit in the making on left, A1 molt limit in the making on right. CC/A1 feathers still in sheath
American Redstart

8. CC/A1 Molt Limits
Vireos
More A1 molt limits

9. Exceptions to the Rule (for CC/A1 moltlimits)
Common Yellowthroats and White-eyed Vireos can often have a more extensive molt including outer PP and inner SS.
If all the alula look uniform, for those species mentioned above the line, molt can be eccentric. Look for some outer primaries and inner secondaries to be replaced. The color of the shaft (rachis) can be particularly helpful when looking at flight feathers. The shaft is typically darker/blacker on a molted feather vs. brown on a retained juvenal feather.
REVI do have an A1 molt limit as HY in the fall, of course a Brown eye = HY and a Red eye = AHY, in the spring, however, all should be aged AHY. It seems that some wing feathers are replaced over the winter and returning birds in the spring no longer show an A1 molt limit. This is not completely understood and more study is needed.

10. CC/A1 Molt Limits + tertials Emberizids
Arrows pointing to the replaced feathers, an A1 molt limit on the top (note this bird abnormally had 4 alula feathers) and a molt limit in the tertials on the bottom
Emberizids

11. CC/A1 Molt Limits + tertials
Note the molt limit in the secondaries (all three tertials, S 7-9 have been replaced). Note also the accidental loss and replacement of a couple inner flight feathers (blue arrow), Adventitious molt should not be used to age birds

12. + tertials (and sometimes more)
CC/A1 Molt Limits
+ tertials (and sometimes more)
This particular HY/SY had a very extensive molt. In this slide, the feathers marked with the arrows are the only ones retained juvenile (molt limit between P1 and 2 and S2 and 3). Note also the appearance of the pp covs. Very broad and rounded (contradicting most descriptions for juvenile pp covs Pyle), but as mentioned before, shape is not a reliable characteristic alone. Look also for the very washed out, brown appearance. The shafts are much browner in comparison to the molted GCovs, no sheen, etc… Overall, just a much duller feather.
Spizella and Melospiza Sparrows

13. Turdid and Mimid Families
GC Molt Limit
Turdid and Mimid Families
Thrush molt limits are typically in the inner GC. This photo shows the classic tear drop on the 8 retained outer GCovs. GC 9 and 10 have been molted. This is a very common pattern for this family of birds.
Gray-cheeked Thrush

14. Turdid and Mimid Families
GC Molt Limit
Turdid and Mimid Families
Using teardrops on GCovs alone is dangerous. This slide shows some exceptions to the tear drop rule. The top photo is of a typical HY bird, but the bottom photo is also a young bird (molt limit between GC 6 and 7). Note, NO teardrops on the greater coverts.
The overlay picture is an adult bird WITH SOME buffy tips and shaft streaking on the GCovs and LC’s/MC’s (lesser and median coverts), However, look also for the uniform appearance of all the GCovs and difference in the quality of the primary coverts between the adult and the young bird (as mentioned in the previous slide of the Song Sparrow),
Swainson’s Thrush

15. Turdid and Mimid Families
GC Molt Limit
Arrow showing the molt limit. The outer four GC are retained juvenal
Gray Catbird

16. Turdid and Mimid Families
GC Molt Limit
“molt limit in the making” Outer four GCovs retained juvenal
Eastern Bluebird

17. Turdid and Mimid Families
GC Molt Limit
The left photo is an HY/SY bird with a somewhat extensive molt, note that A2, S8 and 9 are molted. The photo on the right is an AHY/ASY bird, note the uniform appearance of all of the wing feathers on the adult and the difference, again, in the appearance of the pp covs between the adult and the immature bird.
American Robin

18. Often an extensive molt including all GC, CC, alula, tertials, additional inner secondaries and outer primaries
In the top photo, all LC/MG/Gcovs, and alula molted, as did P6-9 and S6-9. In the bottom photo, all of the same coverts molted along with P4-9 and S You can bracket (as shown in the top photo) the retained juvenal flight feathers in both of these cases.
Species like the INBU, EATO, RBGR, etc. where the males have such distinctive/contrasting plumages, can be lessons for learning molt patterns in these species. This can be helpful in looking for molt limits in females of the same species….next slide.
Cardinalids

19. Often an extensive molt including all GC, CC, alula, tertials, additional inner secondaries and outer primaries
Bracketed feathers are retained juvenal, everything else except for the ppcovs has been molted
Indigo Bunting

20. Complete or nearly complete molt
Northern Cardinal
Swallows
Icterids
Presence of molt limit = HY/SY
Absence of molt limit = U/AHY

21. Complete or nearly complete molt
Icterids can retain underwing coverts
Molt limits among the underwing coverts, There often is no real consistent pattern for retained juvenal feathers on the underwing. Look for scattered molted and retained juvenal feathers

22. Complete or nearly complete molt Icterids can retain underwing coverts
Molted feathers among the underwing coverts. Much less extensive than previous slide, arrows pointing to molted feathers
Brown-headed Cowbird

23. Molt restricted to LC/MC = Difficult to age
Kinglets
For these species, molt limits are not helpful for ageing because the 1st prebasic molt is so limited. So, other characteristics may be useful. Tail shape is more reliable in kinglets than in most other species, when used in combination with the overall appearance of the PPcovs. Once skull pneumatization completes, nuthatches should be aged U/AHY. Tricks for ageing some more of these difficult species are on the following slides.

24. A few “Tricks of the Trade”
Ageing Goldfinches is easy, look for a buffy tip on the carpal covert. Adults AHY/ASY lack the buffy tip and often have a brighter yellow shoulder. The upper left hand photo is an adult bird, no buffy tip on the carpal (This is an example of an adult without a very bright yellow shoulder). The shoulder looks similar to the bird in the lower left photo, which is an HY/SY, note the buffy tip on the carpal covert. The upper right hand photo is of an adult bird, bright yellow shoulder and no buffy tip, some adults may show a white tip on the carpal covert. The bottom right hand photo is an HY/SY bird and the only female of the four (brownish wing vs. jet black)..

25. A few “Tricks of the Trade”
In the spring/summer, AMGO’s are the ONLY birds that you can use the prealternate molt for ageing. Only SY birds molt their inner GC coverts as part of their prealternate molt in late winter/spring. Note the 5 molted inner GC in the photo above.
American Goldfinch

26. A few “Tricks of the Trade”
In the fall, juvenile SWSP’s have a yellow/buff lore and eye stripe vs. a clean gray lore and eye stripe on adults (bird in the photo on the right). This trick is only useful in the fall as the yellow eye stripe is replaced over winter during the prealternate molt.
Swamp Sparrow

27. A few “Tricks of the Trade”
Note the white tip on A2 in the photos above. On an adult, photo on the left, the white wraps all the way around the tip of the feather. HY birds just have a white spot on the A2 feather. Notice, also the A1 molt limit on the HY bird in the photo on the right.
Black-and-White Warbler

28. Finally, this photo does not show it but in Swainson’s Thrushes, in addition to the molt limit in the GCovs, the feathers under the largest alula feather (A3) can have buffy shaft streaks. If you slide A3 to the side and there are buffy shaft streaks on the under alula coverts = HY/SY, lack of shaft streaks does not necessarily = adult (AHY/ASY).
Swainson’s Thrush