Estimates of wear rates in metal bird bands, with applications for survival and movement models of marked individuals

Abstract

Banding allows identification of individual birds, and many investigators use data from recaptured or recovered birds to infer population parameters, including survival rates, migration rates, and recruitment rates. Such analyses often assume that band loss is negligible, but wear rates have been found to differ markedly among different band sizes, band metals, and species in the few cases where wear rates have been determined. However, rapidly wearing bands may be over‐reported in the published literature relative to slowly wearing bands for two reasons. First, researchers publish reports of rapidly wearing bands as a warning to other researchers, but may not publish reports of bands wearing slowly. In addition, sampling error may result in over‐ or underestimation of wear rates. At the extreme, underestimates of wear rates may imply that bands gain mass while worn (i.e., have negative wear rates), whereas extreme overestimates look like rapid wear; only extreme underestimates, not extreme overestimates, are unpublishable due to their a priori implausibility. Hence, the existing literature on band‐wear estimates is likely upwardly biased relative to the true distribution of wear rates across species and band metals. Using routinely archived returned bands from the Australian Bird and Bat Banding Scheme for the period from 1963 to 2005, we estimated wear rates of bands applied to 173 species, five band metals, and 236 species/band size/band metal combinations. Band wear rates were generally well‐explained by band metal and species functional group, i.e., birds of prey, waterbirds (shorebirds, herons, and ibises), passerines, waterfowl (ducks, geese, and swans), rails, seabirds, parrots, and other non‐passerines, but some species had highly divergent wear rates compared to other species in their functional group. We also found that published estimates of wear rates were, on average, more rapid for a given metal type than determined from our analyses. We suggest that publication biases favoring publication of estimates of more rapid wear rates may drive the contrast between estimated wear rates in our analyses and published estimates.

Colour-ring wear and loss effects in citizen science mark-resighting studies

“…The rates of ring wear and loss may vary among and within species depending on behaviour and habitat (Harris 1980). Rates of ring wear or loss may also depend on the material used or the background colour of the ring, for example plastic colour-rings generally wear at faster rates than steel or aluminium rings (Koronkiewicz et al 2005;Sandvik et al 2005;Baylis et al 2018). Darvic colour-rings have been recommended for shorebird studies in recent years, which are made from a pressed PVCU sheet and is colour-fast, hard wearing and malleable (Ward 2000;Robinson et al 2005).…”

A macrorhynchos-like Eurasian Nutcracker (Nucifraga caryocatactes) in the Dolomites with a very abraded ring: an aged immigrant, or a locally born bird?

“…While an aluminium ring worn by a common raven (Corvus corax) for 41 months may still appear legible in a photograph, these birds may lose aluminium rings through wear after 10 to 15 years (Bedrosian & Craighead, 2007). Aluminium rings on passerines wear at about 3% of their mass per year (Baylis et al, 2018), and judging from my photographs, the mass loss of the ring on the bird being studied is not less than 30%. Therefore, assuming a comparable ringing date (about 10 years before my observation), my first explanation would have been unlikely.…”

Band Wear and Effects on Recovery and Survival Estimates of Diving Ducks

“…Additionally, a post hoc review of our data shows that the average number of years between banding and recovery for doublebands from both lesser scaup and redheads was almost identical whether hunters sent them to us for evaluation or chose not to participate. Baylis et al (2018) suggest that studies motivated by observed excessive band wear can overestimate band wear as an overall problem. However, as we observed, loss of contact information influences the likelihood of return once recovered and could result in samples being biased toward recovered bands that are more legible, depending on the species of focus.…”

“…Baylis et al (2018) suggest that studies motivated by observed excessive band wear can overestimate band wear as an overall problem. However, as we observed, loss of contact information influences the likelihood of return once recovered and could result in samples being biased toward recovered bands that are more legible, depending on the species of focus.…”