Great bowerbirds create theaters with forced perspective when seen by their audience

Birds in the infraorder Corvida [1] (ravens, jays, bowerbirds) are renowned for their cognitive abilities [2–4], which include advanced problem solving with spatial inference [4–8], tool use and complex constructions [7–10], and bowerbird cognitive ability is associated with mating success [11]. Great bowerbird males construct bowers with a long avenue from within which females view the male displaying over his bower court [10]. This predictable audience viewpoint is a prerequisite for forced (altered) visual perspective [12–14]. Males make courts with gray and white objects that increase in size with distance from the avenue entrance. This gradient creates forced visual perspective for the audience; court object visual angles subtended on the female viewer’s eye are more uniform than if the objects were placed at random. Forced perspective can yield false perception of size and distance [12, 15]. After experimental reversal of their size-distance gradient, males recovered their gradients within 3 days, and there was little difference from the original after 2 wks. Variation among males in their forced-perspective quality as seen by their female audience indicates that visual perspective is available for use in mate choice, perhaps as an indicator of cognitive ability. Regardless of function, the creation and maintenance of forced visual perspective is clearly important to great bowerbirds and suggests the possibility of a previously unknown dimension of bird cognition.

The Great Western Woodlands : an introduction to the last, vast temperate woodland on earth

At 16 million hectares, the Great Western Woodlands is the world's largest remaining temperate woodland. Here, the woodland birds so decimated in other parts of Australia still survive and thrive. The size of the area ensures that species have the capacity to follow their preferred food resources across the entire landscape. The article outlines conservation efforts in the woodlands to date.

The impacts of recycled water on Great Western vineyard soils

Recycled water has facilitated expansion of viticulture in Great Western, Victoria. The recycled water is of medium salinity, and has high concentrations of nutrients and sodium. Irrigation has resulted in increased topsoil EC, pH, and ESP. Laboratory studies identified spatially heterogeneous soils which present a risk of groundwater and offsite contamination.

Dean's great discovery : multiplication, division and fractions

Multiplication, division and fractions are 'hotspots' for students in the middle years with many students experiencing difficulty with these concepts (Siemon, Virgona & Cornielle, 2001). Arrays effectively model multiplication and help children develop multiplicative thinking and learn multiplication facts (Young-Loveridge, 2005). In this article we show how an open-ended array problem enabled a Grade 5/6 student to think about the relationship between multiplication, division and fractions. In the article we describe the project and 'hot spot' mathematical tasks that we used and provide some background on multiplicative thinking before presenting the case and a commentary (Western Melbourne Roundtable, 1997) of one student's exploration. This case was documented whilst we were working on a collaborative project with a team of upper primary teachers and a group of pre-service teachers at a local primary school.

'It's not enough for the work of art to be great' : children and young people as museum visitors

This paper examines trends in the understanding of children as visitors to art and natural history museums. It begins by examining research into the qualities of engagement by museum visitors generally. It then addresses the specific challenges posed by children as visitors, and the responses developed by museums to enhance their engagement. Three strategies are identified: social/family-centred interactivity, immersive experiences and engagement through interpretive dialogue. The three examples of programs of children’s engagement examined in this paper represent a major departure from such models towards a profoundly social form of interaction. The paper argues that these strategies are museums’ responses to shifts in pedagogical theory, and have been developed to increase the engagement of the child-visitor with exhibitions. Such strategies represent a genuine engagement between adults (both museum staff and parents) and children, and an opportunity for children to define the experience of cultural engagement. The consequence of this is a redefinition of the cultural role of museums in relation to children.

Response to comment on "Illusions promote mating success in great bowerbirds"

Borgia et al. raise some questions about our recent study showing that great bowerbirds create visual illusions that are used in mate choice. We address them by providing further details about our methods and results. We also provide detailed descriptions of our geometric calculations to address their measurement and analysis questions.

Illusions promote mating success in great bowerbirds

Sexual selection studies normally compare signal strengths, but signal components and sensory processing may interact to create misleading or attention-capturing illusions. Visual illusions can be produced by altering object and scene geometry in ways that trick the viewer when seen from a particular direction. Male great bowerbirds actively maintain size-distance gradients of objects on their bower courts that create forced-perspective illusions for females viewing their displays from within the bower avenue. We show a significant relationship between mating success and the female's view of the gradient; this view explains substantially more variance in mating success than the strength of the gradients. Illusions may be widespread in other animals because males of most species display to females with characteristic orientation and distance, providing excellent conditions for illusions.