SeEtta et al.: First off, one really needs to know what one means by "juvenile." In birds, this term is usually restricted to birds in juvenal plumage (= first basic plumage). Once an individual initiates a post-juvenal molt, it is not considered juvenile. Of course, detecting that point is virtually impossible, but knowing that most passerines initiate such a molt in summer or fall means that by the end of September, few birds are considered juveniles. There are quite a few exceptions, but Scissor-tailed Flycatcher (STFL) is not one of them. Which gives me a perfect opportunity to once again push the importance to birders of owning -- and reading -- Peter Pyle's Identification Guide to North American Birds, parts I and II (1997 and 2008; Slate Creek Press -- www.slatecreekpress.com/). Though it's considered by many "just" a bird-banding guide, the information available there is very useful to field ID. In fact, everything queried in SeEtta's post is noted there (in part I; pgs 266-267). [The usual caveats apply -- I have no financial interest in the publication.] The preformative molt in STFL is initiated on or near the breeding grounds, suspended during migration, and completed on the winter grounds (pg 267; Molt). Assaying the importance of the presence of strong color in the axillar region in SeEtta's bird is entirely dependent on how extensive the part of the molt conducted on the breeding grounds is if the bird were a first-cycle bird. So, on the sole basis of axillar color, the bird is not ageable, thus is also not sexable. However, other features in SeEtta's pictures provide some clues, but also some confusion. In the top picture, the apparent outermost primary is growing -- one can see the whitish sheath at the base of that feather that is characteristic of growing feathers. The confusion here is engendered by the fact that we cannot know which primary that is, because part of the wing is hidden behind the wire and we cannot count feather tips. I suspect that it is not the actual outermost primary (10th primary or p10), because it has a nice rounded tip, which adult Scissor-tailed Flycatchers do not sport, and because first-cycle STFLs do not replace their outer primaries (that they grew in the nest). Adult kingbirds (and STFL is an aberrant kingbird) have emarginated p10s, that is the inner web is cut away some distance from the feather tip. Males have considerably deeper emarginations than do females, thus that one feather can often tell us not only the age, but also the sex of these birds (see Fig. 181, pg. 267, in Pyle part I). Though I believe that SeEtta is right, and the pictured bird is an adult female (at this time, one cannot discern any ages in the species other than adult and 1st-cycle) for a number of reasons, with the combination of flight-feather molt and location (adult STFLs conduct their prebasic molts on or near the breeding grounds) making for certainty. However, because the outer primaries have not completed growing, I believe that the outer tail feathers -- which are the long ones -- have also probably not completed growth, as those are grown at the same time in most passerines. So, this bird will get longer-tailed, answering SeEtta's question about the relatively short tail. Sincerely, Tony Leukering Villas, NJ
Topic: Scissor-tailed Flycatcher near Holbrook Reservoir in Otero Co SeEtta Moss <[email protected]> Sep 25 12:44AM -0600 ^ Late this afternoon I found a Scissor-tailed Flycatcher a short distance southeast of Holbrook Reservoir. I spotted it a short distance south of CRFf just west of CR26. It was foraging around the area where there are irrigation ditches. I observed and photographed it for around 15 minutes and got some very interesting photos. I saw it appearing to cast out a pellet and quickly took photos of this behavior which I had no idea that a Scissor-tailed Flycatcher or any other flycatcher species would engage in. When I got settled into my motel in Lamar and looked it up on* Birds of North America* online I found that this species does "occasionally" cast pellets composed of insect parts. I got a series of 4 photos of the bird engaging in casting a pellet including the last one showing the pellet falling at the bottom of the pic. I have uploaded these and more photos of this bird to my Birds and Nature <http://birdsandnature.blogspot.com/> blog including a discussion of the behavior. This Scissor-tailed Flycatcher showed an orangish colored axillary patch which I read in BNA is not found in juvenile birds. I think it may be a female adult or immature with this axillary patch and shorter tail feathers than an adult male but I am not that familiar with the aging and sexing of this species so would welcome some feedback on this. The bird was associating with other flycatcher species--a Cassin's Kingbird and several Western Kingbirds. SeEtta Moss Canon City (currently in Lamar) Personal blog @ http://BirdsAndNature.blogspot.com<http://birdsandnature.blogspot.com/> Blogging for *Birds and Blooms* magazine @ Birds and Blooms blog southcentral/ <http://birdsandbloomsblog.com/category/southcentral/> -- You received this message because you are subscribed to the Google Groups "Colorado Birds" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/cobirds?hl=en.
