Canadian Snow Bunting Network (CSBN) Winter Snow Bunting Banding Protocol

Transcription

1 Canadian Snow Bunting Network (CSBN) Winter Snow Bunting Banding Protocol Thank you for joining our network of winter banders! Your contribution is extremely important in understanding the wintering and migratory biology of this species, which is thought to be in decline. The information below will help you get started with trapping, banding and data collection for your winter flocks. Please feel free to contact us anytime with additional questions or concerns. Thanks again for your help and good luck! Why catch and band Snow Buntings? Snow buntings (Plectrophenax nivalis) are found globally from the low to the very high Arctic, but North American populations are thought to have declined by 64% in the past 40 years (National Audubon Society). Christmas Bird Counts and band recovery reports have provided valuable information on population trends and broad migratory movements, respectively, but to understand the mechanisms behind this potential decline, we are attempting to monitor breeding, migratory and wintering behaviour across Canada. Snow Buntings are believed to be highly nomadic in the winter as they move across and interact with the landscape, but we know little about the sex and age-class structure of these flocks and even less about their within- and across-year movement patterns. Our initial goal is to understand how wintering flocks are structured and how this structure may change geographically and temporally in response to factors such as local climate. This work will improve our understanding of the degree of seasonal connectivity within wintering flocks and what factors drive their movement behaviour. Our second goal is to improve band recovery rates by expanding the network of volunteer bird banders in order to begin linking specific wintering and breeding populations to ultimately help direct and optimize future conservation efforts for this important species. Winter banding data will also aid us in understanding survival and determining whether Canadian populations are indeed experiencing this steep decline.

2 Trap design: Walk-in type traps are very useful for large flocks of buntings and are best made of 1 x 0.5 hardware cloth (sometimes called welded wire) held together with J-clips. A design provided by David Lamble that has worked well in the past is 36 x 24 and 8 high with four 3 x 3 tunnel entrances 7 long, one at each corner (see below). Each tunnel has a 3 x 3 opening at the end that birds can use to get to the feed in the middle of the trap. The trap can have 1-2 extraction doors (depending on arm length) in the top remove birds. (Note that David s design is divided into 2 compartments for ease of extraction. A 3 foot trap would be very hard to get birds out of.) J-clips Tips for baiting and trapping: Cracked or Cut Corn can be purchased relatively inexpensively ($10/50lb bag). Bait in an open agricultural field (eg corn stubble) where birds have been seen recently. Concentrate the corn only in a few places where you intend to put traps. Once birds have found the site, you will have better luck getting them to actually go in the trap. Re-bait daily to establish a location where the birds know to return to feed. Data collection: please see Microsoft Excel template provided with protocol Record the number of traps you use & the total trap hours per day for each day banding Record general weather (T, wind, cloud cover) and an estimate of snow cover/depth In addition to the data submitted to the Bird Banding Office, here is an example of the types of data we are looking for, ideally in a Microsoft Excel file: Year Month Day Band # Species Age Sex Wing Chord Weight Fat Score Notes How to collect measurements: We measure: 1. Un-flattened wing chord, 2. Weight to 0.1 or 0.01g, 3. Fat scores according to this scale (see image): Score Furculum Abdomen 0 No fat, region is concave No fat 1 Trace, deeply concave, < 5% filled, None/trace (small patches) 2 Thin but complete layer, < 33% Trace/thin layer 3 >50% filled Small patches 4 > 66% filled, level with clavicles Covering pad, slight mound 5 Slightly bulging Well mounded 6 Bulging greatly Greatly distended mound 7 Pads of furculum & abdomen meet 2

3 Identifying Age and Sex: The table below outlines how to correctly age and sex Snow Buntings. An additional detailed identification key produced by David Hussell can be provided if the description below seems unclear. Photos courtesy of D. Hussell and A. Heagy. MALES Hatch/Second-Year (HY/SY) Dirty-white secondaries with dark gray streaks, dark gray alula and dark gray primaries. Primary coverts white, sometimes tipped/washed with varying amounts of gray. Note: the white is dirtier than AHY male and the primary colour is gray, not jet black as it is in AHY male. After-Hatch/Second Year (AHY/ASY) Completely white lesser, median, greater and primary coverts and dark black alula and dark black colour on primaries. Note: the white is bright and the primary colour is jet black, not gray, as it is in HY male. 3

4 FEMALES Hatch/Second Year (HY/SY) Lesser and median coverts gray, narrowly tipped with white. Primary coverts all dark. Greater coverts 1-6, have black marks on both webs; more black on inner web, extending closer to tip of feather, than on outer web. After-Hatch/Second Year (AHY/ASY) Lesser and median coverts gray, broadly tipped with white. Primary coverts have extensive white on inner webs. Greater coverts 1-6 have black marks on proximal portions of outer webs, mainly white on inner webs. Female Greater Secondary Coverts First Row: HY; Second Row: AHY. Black is more extensive on inner web than outer web in HYs. In AHYs, inner web is largely white or has large white patch extending across the full width of the web near the middle of the feather. 4

5 Confusing Birds! (the ages of females are often the most difficult to identify by plumage, but you might also expect to find some confusing males as well see discussion below) In contrast the ASY females, these young males are some of the "worst" males I have ever seen. The dark on their primaries is often dark brown as opposed to a charcoal-dark gray and they have a great deal of dark in the mid-upper wing. At first, these birds were confusing to us since they looked like "high quality" ASY females. However, after a few birds they were more easily distinguished due to 1) the quality of the white, 2) body size, 3) patterning on the back, 4) size of the GSCs (larger) and 5) and the presence of a "window" of white (however much reduced compared to ASY males) in their upper wings, whereas even the best-looking ASY females still have continuous pigmented feathers across the upper wing (please note this male has a missing GSC4 as it was collected). Oliver Love Band number has black marks on the outer webs of all greater coverts, much like many ASY females, and unlike most males which usually have at least one greater covert with the exposed surface all white, such that the black wing bar (if present at all) is broken near the middle. That this is a male is indicated by the almost pure white lesser and median coverts. These feathers are moulted in the first (and later) prebasic moult. In females, they are always mottled grey and white, never solid white like the ones on this bird. David Hussell Band number also has dark markings on all greater coverts, but they are more diffuse than on 551 and not really similar to typical males or females. Again, the giveaway is the nearly solid white lesser and median coverts, typical of HY/SY males. David Hussell Thanks again for being a big part of the CSBN. We wish you the best of luck this winter! 5