The balcony levels of the Natural History Museum have been closed following a safety review. There are too few emergency exits from upper levels. The National Museum of Ireland has developed a plan to address this but funding for that plan is not yet available.
What you are missing:
Birds illustrate perfectly a critical issue for all animals: the need to reproduce. Without healthy offspring growing up in a suitable habitat, there would be no descendants.
Birds are more often heard than seen, their calls may be more identifiable than their plumage. The eagle owl Bubo bubo of European forests is the largest of a group of birds well known for their calls. The hooting of owls serves a number of purposes, as do the calls of most birds. They advertise the bird’s presence but also run the risk of attracting predators, so they must be of benefit to be worth the danger. Calls may be used to mark out territories. Each bird needs an area of its own that can supply enough food for its needs and is free of birds of the same species competing for that food. Calls also indicate the health and sex of birds and are key factors in the mating game.
Many tropical birds are brightly coloured and visually striking, none more so than the toucan, with its enlarged bill. There are 37 species in the toucan family, including Ramphastos vitellinus, which inhabits rainforests of the Amazon River banks in Brazil.
Large bills are specially adapted for picking fruit from awkward places; the fruit is then swallowed by tipping the head back with the bill upright. Bright patterns help to confuse predators by breaking up the outline of birds in the dappled light of the forest. Males of many bird species are brightly coloured, a feature that can be used by females to judge health as a measure of freedom from parasites. A healthy male is always preferred for breeding purposes and gives a greater chance of sturdy offspring.
Colour is not the only feature that female birds use to judge potential suitors. Bower birds, such as Ptilonorhynchus violaceus from eastern Australia, make elaborate stages on the forest floor on which to perform. First the male lays a path of twigs along the ground, followed by two rows of vertical twigs meeting at their tips to form an enclosure reminiscent of a shady avenue. The structure is decorated with brightly coloured objects scavenged from the neighbouring forest. This behaviour illustrates the health and success of males, as those with the most impressive bowers are obviously good providers, with additional energy available for showing off. A female bird convinced by this display will mate in the bower and retire to a nest in a nearby tree to lay her eggs.
Image is not everything in bird mating rituals. Lyre birds are dull-coloured by comparison with many birds but make up for this with impressive tail feathers, which the male uses for display during courtship. Females of Menura superba are similar to males but without the lyre-shaped tail feathers. The males are superb mimics of the bird song of other species and use a variety of sounds to impress friend or foe. Song is a good indicator of health and is often used by other birds to assess the size, health or strength of potential competitors and mates.