Moult in captive Regent Honeyeaters Xanthomyza phrygia (original) (raw)

moult: AnRPackage to Analyze Moult in Birds

Journal of Statistical Software, 2013

Moult is the process by which birds replace their feathers. It is a costly process in terms of energy and reduced flight ability but necessary for the maintenance of the plumage and its functions. Because birds generally avoid to moult while engaged with other energy demanding activities such as breeding and migration, the analysis of moult data gives insight into how birds fit this life stage into the annual cycle, on time constraints in the annual cycle, and on the effects of environmental variables on the timing of moult. The analysis of moult data requires non-standard statistical techniques. More than 20 years ago Underhill and Zucchini developed a likelihood approach for estimating duration, mean start date and variation in start date of a population of moulting birds. However, use of these models has been limited, mainly due to the lack of user-friendly software. The moult package for R implements the Underhill-Zucchini models, allowing the user to specify moult models in a regression type formula. In addition the functions allow the moult parameters (duration, and mean and variation in start date) to depend on explanatory variables. We here describe the package, give a brief summary of the theory and illustrate the models on two datasets included in the package.

The timing and duration of moult in adult Starlings Sturnus vulgaris in east-central England

Ibis, 2008

The timing and duration of primary moult were estimated for wild adult Starlings Sturnus vulgaris near Monks Wood in 1977-78, and for captive birds in 1999. The model of Underhill and Zucchini (1988) was modified to allow for a non-linear increase in the moult score, based on scores of captive birds. For wild birds, estimates of moult duration in 1977 and 1978 were 100 days and 98 days, with mean and standard deviation in start dates of 6 June and 7.3 days in 1977, and 2 June and 9.7 days in 1978. For captive birds, moult duration was 85 days, with mean and standard deviation of 3 1 May and 4.1 days. Differences between these estimates and those reported for other wild and captive Starling populations are discussed We apply models of avian moult to estimate the timing and duration of moult in adult Starlings Sturnus vulgaris from samples of birds obtained near Monks Wood (1977-78), eastern England, where British breeding Starlings are resident all year-round, and from studies on captive birds in 1999. Although several previous studies have been made of Starling moult, all were in regions different from our own, and for various reasons none is directly comparable with ours. The most thorough previous study refers to South Africa where the Starling was introduced more than a century ago (Cooper & Underhill 1991), and where the different latitude affects both the timing and duration of moult. Ginn and Melville (1983) gave estimates of moult timing and duration in free-living birds in Britain on the basis of moult cards. General details of moult in different parts of the natural range can be found in Dement'ev and Gladkov (1954) and Cramp & Perrins (1994). Studies on captive birds in Scandinavia (Lundberg & Eriksson 1984) and Britain (Dawson 1987, 1994) were not comparable because birds were held under artificial daylength, which affects both timing and duration of moult.

Flexibility in the timing of post-breeding moult in passerines in the UK

Ibis, 2015

Higher temperatures resulting from climate change have led to predictions that the duration of the breeding season of many temperate bird species may be changing. However, the extent to which breeding seasons can be altered will also depend on the degree of flexibility in processes occurring at other points in the annual cycle. In particular, plasticity in the timing of post-breeding moult (PBM) could facilitate changes in the timing of key events throughout the annual cycle, but little is known about the level of withinand between-species plasticity in PBM. As part of the British Trust for Ornithology (BTO) Ringing Scheme, many ringers routinely record moult scores of flight feathers, and these can be used to provide information on the annual progression of PBM for a range of species. Here we use ringing data to investigate patterns of PBM in 15 passerines, as well as data from the BTO Nest Record Scheme to relate these differences to the timing of breeding of these species across the UK. We find considerable variation in both the mean start (19 May-29 July) and duration (66-111 days) of PBM between species, but find no evidence that species starting PBM later in the season complete it any faster. However, there is considerable within-species variation in PBM, particularly for multi-brooded species; PBM starts later and is completed in less time when the duration of the breeding season (difference between first and last nests) is longer. This implies that a later end to breeding can be compensated for by faster PBM, and that advances in breeding could lead to earlier and slower PBM. Our findings suggest that adaptation of PBM in response to climate-mediated changes in the timing and duration of the breeding season is possible. However, the requirement to complete PBM prior to migration or the onset of winter might constrain the extent to which breeding seasons can lengthen, especially for later nesting species.

Molting while breeding? Lessons from New World Tyrannus Flycatchers

Journal of Ornithology

Songbirds must annually undergo two energetically demanding but important activities: breeding and feather molt. Due to the high energetic investment that each demands, these two events are generally not carried out simultaneously. However, substantial variation in the level of annual reproductive investment among populations may result in variation in molt-breeding overlap between them. With the goal of understanding whether different songbird populations overlap molt and breeding, and, if so, to determine directions for research on the potential tradeoffs involved, we describe the relationship between clutch size, molt, and energetic condition within a genus of New World Flycatchers (Tyrannus). Of 219 Flycatchers sampled, only one individual molted flight feathers while breeding, suggesting that molting flight feathers and breeding simultaneously is too energetically expensive at any clutch size. However, some Flycatchers molted body feathers during the breeding season. When we tested for an effect of clutch size, sex and energetic condition on body molt intensity during the breeding season, only clutch size and sex had significant effects, with a negative effect of clutch size on body molt intensity in males but not in females. Based on these results, we develop a set of hypotheses to guide future studies on the potential tradeoffs between investment in reproduction and molt.

Incubation by young, nonbreeding birds: potential versus realization of behaviour

Canadian Journal of Zoology-revue Canadienne De Zoologie, 1987

. Incubation by young, nonbreeding birds: potential versus realization of behaviour. Can. J. Zool. 65: 2567-2570. Incubation behaviour is described in nonbreeders of two species of birds. Among communally breeding pukeko (Porphyrio porphyrio melanotus), some subadult members of a group incubate eggs but are not involved in courtship or mating. In one population of white-rumped swiftlet (Aerodramus spodiopygius), a single nestling is reared initially at each nest but that nestling incubates a second egg before fledging. The standard proximate and ultimate explanations given for parental incubation would be difficult to apply in these cases. Incubation of eggs might therefore be better understood by looking at the circumstances that cause birds to realize their potential for exhibiting incubation behaviour. JAMIESON, I. G . , CRAIG, J. L., et MINOT, E. 0 . 1987. Incubation by young, nonbreeding birds: potential versus realization of behaviour. Can. J. Zool. 65 : 2567-2570. Un comportement d'incubation existe chez les oiseaux non-reproducteurs de deux especes. Chez des Poules sultanes Porphyrio porphyrio melanotus qui nichent en groupe, quelques individus sub-adultes d'un groupe peuvent couver des oeufs, sans s'impliquer ni dans les comportements de cour, ni dans les comportements d'accouplement. Dans une population du martinet Aerodramus spodiopygius, un seul petit est Cleve au depart dans chacun des nids; ce dernier couve cependant un second oeuf avant de quitter le nid. Les avantages a court et a long termes normalement Cvoques pour expliquer le comportement d'incubation chez les adultes s'appliquent difficilement dans ces cas. 11 faut donc plutbt essayer de comprendre ce comportement en examinant les circonstances qui le declenchent. [Traduit par la revue]

Moults and weights of captive RedpollsCarduelis flammea

Journal of Ornithology, 1969

From an ecological standpoint, moult is best studied in wild birds, but since few are caught more than once during the course of moult, it is normally difficult to follow the moults of partlcular individuals. In captivity, on the other hand, birds can be examined as orten as required and can thns provide precise information on the timing and duration of moult in particular feather tracts, on the time taken for individual feathers to grow, the rate at which they are shed, and on other aspects difficult to study in the wild. Caution is needed, however, in the use of such information, for ,birds ,do not always moult normally in captivity and so~mefimes take longer than in the wild (ZmDrER 1966, N~wTON 1967). The paucity of detail on the moults of birds has been stressed by STRrSrMANN ~ STRESEMANN (1966). In this paper, details of moult, weights and pre-migratory fattening are given for 8 captive Redpolls; 6 were of the rate Carduelis flammea cabaret and were caught in their winter quarters near Oxford, England, and 2 were of the larger race C. f. flammea, caught in southern Sweden. Redpolls are easy to keep in captivity and, on some aspects, comparative data are available for wild birds from the studies of EVANS (1966, 1969) in northeast England, and EvA~s et al. (1967) in northern Norway. The birds used here were eaught in autumn 1965 and these observations were made in the following summer. The birds were not allowed to breed, but were housed in a large flight cage until early July, after which each was pur in a separate tage; all had permanent access to food, watet and grit, and were exposed to outside temperatures and the day-lengths of 51x/2° N. In the wild in Scandinavia C. f. flammea would normally moult under longer and colder days than those experienced in Oxford, but by comparison with wild birds (EvANS et al. 1967) this seems not to have affected the moult of the two individuals studied.