Ian McTaggart Cowan’s research while affiliated with University of Auckland and other places

Gross energy intake, excretory energy, and metabolizable energy of both the common starling and the crested myna were obtained at outdoor temperatures through 12 consecutive months. Basal metabolic rates for the two species were determined to be 12.6 and 9.5 cal/g h for starlings and mynas respectively.The thermal response of both species was determined over a range of controlled temperatures between −20 °C and +30 °C, with birds acclimated to the outdoor ambient temperatures of June and November. No seasonal differences were revealed. Starlings were found to have a higher temperature tolerance (above 40 °C) than the crested myna (mean lethal dose (LD50) = 40 °C). The insulating quality of the plumage of the two species was determined by measurements of rate of cooling. Starlings had a relatively lighter total plumage (7% of body weight) than mynas (9.4% of body weight). Even so, the mean insulating value of myna plumage was found to be only 3.4 ± 0.50 × 10−2 cal/g h °C cm2 compared to 6.2 ± 0.50 × 10−2 cal/g h °C cm2 for starling plumage.Mynas were shown to have less tolerance of cold and of heat than the ubiquitous starling.

Two species of starlings (Sturnidae) have established themselves in southwestern British Columbia: the crested myna (Sturnus cristatellus), by escape from captivity about 5897, and the common starling (Sturnus vulgaris), by natural invasion during the 1950's. The crested myna has shown little capacity to expand its range or its population. The common starling is in an active phase of increasing density and distribution. These sympatric populations have been studied over a period of 3 years. This paper reports comparative aspects of reproduction, and resource use by the two species.We have found that the nesting season for starlings was synchronized into definite peaks of nest building, egg laying, hatching and fledging, which was not the case for crested mynas.Clutch and brood sizes were higher in starlings than mynas. Starlings successfully reared more second broods than mynas (38% vs. 9%). Per 100 pairs/annum, starlings contributed significantly more offspring (547 compared to 238) to the sturnid population.Although development of plumage and endothermy were similar in myna and starling chicks, feeding rates, quality of foods, and subsequent growth rates of chicks were significantly different.Egg transplant and heater nest box experiments suggested that poor nest attentiveness and low incubation temperatures maintained by crested mynas resulted in the low hatching and consequent low fledging success.