Characterizing opportunistic breeding at a continental scale using all available sources of phenological data: An assessment of 337 species across the Australian continent

High air temperatures induce temporal, spatial and social changes in the foraging behaviour of wild zebra finches

“…By contrast, a more bimodal distribution of foraging behaviour was found in captive zebra finches in unpredictable food availability conditions, without breeding activity or predation risk (Dall & Witter, 1998). During our study period very few breeding attempts were observed and there was no successful breeding, in line with recent findings showing that arid zone Australian birds typically do not breed in the summer (Duursma et al, 2017). According to theoretical foraging models (Houston et al, 1993), it seems likely that on the hottest days, individuals were refraining from foraging throughout most of the day until it became a little cooler, at which time they needed to forage more intensively to take on food before nightfall.…”

“…The negative relationship between high temperatures and foraging activity we have demonstrated could be interpreted as one cause of the low body size of zebra finches that were reared during hot conditions in the field (Andrew et al, 2018(Andrew et al, , 2017Cunningham et al, 2013) and the avoidance of breeding in summer for arid species generally in Australia (Duursma et al, 2017).…”

“…Foraging behaviour was measured using artificial feeders at the end of the breeding season, between January and February 2017, when the temperatures are typically hottest, that is, we were studying the birds in a period of the year when recent work suggests that they are less likely to breed because of the heat (Duursma et al, 2017). Feeders were placed randomly within a radius of approximately 800 m of the dam (Fig.…”

“…Investigating the relative plasticity of physiological and behavioural traits during short and unpredictable environmental changes ('perturbation resistance potential') can help to define when a change should be considered extreme, indicate how the availability of energetic resources will be affected and predict the degree to which a population will be able to resist projected climates in the future (Wingfield et al, 2017). Extreme temperatures are also likely to compromise reproduction through a number of pathways: a recent analysis on the breeding phenology of over 300 Australian bird species found that, in the hot arid areas of inland Australia, birds typically avoid breeding in the summer months, presumably to avoid the extreme heat during this time (Duursma, Gallagher, & Griffith, 2017). Reproduction may be compromised by the effect of hot weather on reproductive physiology, such as damage to sperm (e.g.…”

Wild zebra finches do not use social information from conspecific reproductive success for nest site choice and clutch size decisions

“…The first assumption is unlikely to be valid for zebra finches and the latter also needs to be put in question. Birds living in arid environments have greatly extended potential breeding seasons, compared with those in the more seasonally predictable northern hemisphere temperate zone (Duursma et al 2017) and in any one year, can also breed multiple times. Shorter intervals between breeding attempts increase the chance that information is still valid for the subsequent brood.…”