On this page, you can learn about some of the discoveries that have come from our study of black swans by reading through the summaries and following links to the scientific papers themselves.
In this study, we investigated how flight responses of black swans are related to their distance from safety (i.e. water). As predicted, swans further from water initiated a flight response earlier than those nearer water. Furthermore, females tended to respond earlier than males, and were more likely to take flight when approached from the water than from land or parallel to the shore. This suggests that they are sensitive to the degree of danger, and that males are bolder than females when confronted with danger.
GUAY, P-J., LORENZ, R.D.A., ROBINSON, R.W., SYMONDS, M.R.E. & WESTON, M.A., (2013). Distance from water, sex and approach direction influence flight distances among habituated swans. Ethology 119: 552-558. doi: 10.1111/eth.12094
We recently conducted a study investigating potential effects of the annual Formula 1 Grand Prix motorsport event held at Albert Park on the black swan population. By comparing population numbers, behaviours and stress levels in black swans before, during and after the event, we found that although the birds do not leave the park or show obvious evidence of changes in behaviour, their stress levels are elevated during the event. This is of potential concern because similar stress differences in bird populations elsewhere are associated with reduced lifespan or breeding success. See here for a report on this study in The Age.
PAYNE, C.J., JESSOP, T.S., GUAY, P-J., JOHNSTONE, M., FEORE, M. & MULDER, R.A., (2012). Population, Behavioural and Physiological Responses of an Urban Population of Black Swans to an Intense Annual Noise Event. PLoS ONE 7(9): e45014. doi:10.1371/journal.pone.0045014
Swans are symbols of monogamy and faithfulness, but do they really live up to this ideal? In this study we used DNA paternity tests to find out about the mating patterns of male and female swans. We discovered that on average one in six cygnets (15%) results from a matings between either the male or female, and a bird other than their partner. These values are unexpectedly high compared to other waterbirds.
KRAAIJEVELD, K., CAREW, P.J., BILLING, T., ADCOCK, G.J. & MULDER, R.A. (2004). Extra-pair paternity does not result in differential sexual selection in the mutually ornamented black swan (Cygnus atratus). Molecular Ecology 13:1625-1633.
This is a rather technical paper that describes the paternity testing methods we developed to enable us to work out who the true mother and sire are of cygnets born to a particular pair.
Black swans engage in a behaviour known as crèching or brood amalgamation. Some time after hatching, cygnets from different broods move from one family to another and so end up being reared by adults other than their genetic parents. A variety of hypotheses have been developed to explain why individuals should engage in this curious behaviour. In this paper, Ken finds that adopted cygnets are more closely related to their ‘foster’ parents than they are to most other swans in the population, raising the intriguing possibility that brood amalgamation involves close relatives.
KRAAIJEVELD, K. (2005). Black swans Cygnus atratus adopt related cygnets. Ardea 93: 163-169
Neck collars are commonly used to identify geese and swans in the northern hemisphere, but possible adverse effects have been investigated in only a few species. Before commencing a large-scale tagging program, we wanted to reassure ourselves that they did not have adverse effects on the birds that wear them. To examine possible effects, we compared the behaviour and condition of a sample of collared swans with that of a group of uncollared swans. We found no differences in the amount of time the birds spent foraging, resting or swimming, and both sets of birds had similar weights. These findings suggest that For more details, please consult the article below:
Members of the public with an interest in research on their local wildlife – often referred to as ‘citizen scientists’ are a potentially vast source of information about urban wildlife. In this paper we review public reports of collared black swans and kangaroos, to evaluate the value and reliability of these public contributions. We find that public reports contribute very substantial and largely accurate data, and consider the potential of web-based interactive tools to encourage public participation in science. For more details, please consult the article below:
Black swans are the only member of the swan family to sport a ruffle of curled feathers on their wings. These curled feathers occur in both males and females, and are prominently displayed during social interactions. We found that these feathers play a role in both sexual and social contexts – swans endowed with more of these feathers are more likely to find a mate, and they also tend to win fights. Males and females of similar display ‘status’ tend to pair up, creating a society with a hierarchy of ‘mutual admiration’. For more details, please consult the article below: