Chic chicks: the evolution of chick ornamentation in rails

Competition over access to food has led to the evolution of a variety of exaggerated visual and vocal displays in altricial nestling birds. Precocial chicks that are fed by their parents also vary widely in appearance ranging from those with inconspicuous coloration to those with brightly colored bills, fleshy parts, and plumes. These ornaments are lost by the end of the period of parental dependence, suggesting they function in competition over parental care. We use a comparative approach to evaluate which ecological or life-history variables may have favored the evolution of conspicuous ornamentation in precocial chicks. We compiled data on chick morphology, ecology, and social organization of species in the Family Rallidae, a group with highly variable downy chicks. Chick ornamentation in the form of brightly colored bills, fleshy patches, or plumes is observed in 36 of 97 species for which downy chicks are described. Phylogenetic reconstructions suggest that nonornamentation is the ancestral state. Chick ornamentation has evolved multiple times within the Rallidae and is significantly associated with large clutch sizes and polygamous mating systems. Chick ornamentation was also weakly associated with adult ornamentation and adult dimorphism. We argue that these results support the hypothesis that lineages with higher levels of sibling competition are more likely to evolve ornamented chicks. Copyright 2004.chick coloration; precocial chicks; Rallidae; sibling competition; signaling

Macrolepidopteran assemblages along an altitudinal gradient in subtropical rainforest - exploring indicators of climate change

Moth assemblages have been widely used to estimate patterns of beta-diversity in forest ecosystems. As part of the IBISCA-Queensland project we examined patterns of diversity in a large subset of night-flying moths along an altitudinal gradient in subtropical rainforest. The permanent IBISCA-Queensland transect located in Lamington National Park, south-east Queensland, Australia, spans altitudes from 300 metres (m) to 1100 m above sea level (a.s.l.) within continuous, undisturbed rainforest. We sampled four replicate plots at each of five altitudes (300, 500, 700, 900, 1100 m a.s.l.). A total of 11 379 individual moths were sampled, belonging to approximately 865 morphospecies. Moth assemblages displayed a strong altitudinal signal at each of two sampling periods (October 2006 and March 2007). The results show that cloud forest above 900 m a.s.l. where Nothofagus moorei becomes dominant, contains a number of moth species that are restricted to the high elevation forest and these species may be most threatened by climatic change. The analyses presented here suggest a set of 18 moth species which may be useful as part of a multi-taxon predictor set for future monitoring of the impact of global warming on forest biodiversity. © The State of Queensland (Queensland Museum) 2011.Link_to_subscribed_fulltex

Effects of habitat characteristics and climate on the distribution and colouration of Dusky Moorhens (Gallinula tenebrosa) in south-east Queensland

We determined which factors predict the presence and abundance of Dusky Moorhens (Gallinula tenebrosa) at wetlands by surveying the ecological and habitat characteristics of 62 sites across south-east Queensland. Moorhens were observed in 48 of the sites sampled. They were more likely to be found at sites surrounded by taller terrestrial vegetation and where free-floating and attached aquatic vegetation was more abundant. The number of moorhens found at a site increased in relation to vegetation height, the abundance of attached aquatic vegetation and the number of purple swamphens observed. These results suggest that there are ecological constraints on the distribution of moorhens, and that food abundance and the availability of suitable nesting sites determine the overall distribution and abundance of moorhens in wetlands. Adult moorhens develop brightly coloured fleshy frontal shields, bills and legs when breeding, although in some populations birds maintain year-round colouration. We observed year-round breeding colouration in 23 out of 34 sampling sites that had moorhens and were surveyed in August. Coloured moorhens were found during winter at sites with higher minimum winter temperatures, and more abundant free-floating and submerged leafy vegetation. In addition, higher proportions of moorhens were coloured at sites with higher mean minimum temperatures. The retention of year-round breeding colouration appears to be restricted to areas with warmer winter temperatures and more abundant food. The results suggest that areas not occupied by moorhens are of inadequate quality to support breeding populations. We suggest that ecological constraints on independent breeding in Dusky Moorhens may have favoured the evolution of their unusual cooperative breeding system, which involves frequent mate-sharing by both sexes

Macrolepidopteran assemblages along an altitudinal gradient in subtropical rainforest - exploring indicators of climate change

Volume: 55Start Page: 375End Page: 38

Imitating the neighbours: vocal dialect matching in a mimic–model system

Vocal mimicry provides a unique system for investigating song learning and cultural evolution in birds. Male lyrebirds produce complex vocal displays that include extensive and accurate mimicry of many other bird species. We recorded and analysed the songs of the Albert's lyrebird (Menura alberti) and its most commonly imitated model species, the satin bowerbird (Ptilonorhynchus violaceus), at six sites in southeast Queensland, Australia. We show that each population of lyrebirds faithfully reproduces the song of the local population of bowerbirds. Within a population, lyrebirds show less variation in song structure than the available variation in the songs of the models. These results provide the first quantitative evidence for dialect matching in the songs of two species that have no direct ecological relationship

Detecting Biodiversity Changes Along Climatic Gradients: The IBISCA-Queensland Project

The IBISCA-Queensland project established 20 permanent plots over an altitudinal range of 300 m to 1100 m above sea-level (a.s.l.) in rainforest within Lamington National Park, south-east Queensland. Four replicate plots were established at each 200 m interval, representing an average temperature change between altitudes of about 1.5°C - a full range of approximately 7.5°C. The project aimed to identify which animal and plant groups are likely to be most sensitive to climate change and which ones can best be used as indicators for monitoring such change. Full vegetation analyses were carried out at each plot and basic climatic and soil data collected. Over an 18 month period insect collections, using a wide-range of trapping methods, were made and specific projects carried out by more than 55 scientists from 14 countries. This paper summarises the history and goals of the project and the general 'IBISCA' model within which it was conceived. Site locations are presented, as is an outline of the specific trapping programme and more specific projects carried out within the broader objectives of IBISCA-Queensland. The strengths and weaknesses of the IBISCA approach are discussed. The first comparative syntheses are anticipated and a broader context for future work is defined. © The State of Queensland (Queensland Museum) 2011.Link_to_subscribed_fulltex