Housing developers in Australia could get into developing space for birds and animals. Birds’ space is at a premium in most nesting sites with spring approaching. Climate change has pushed it ahead earlier than usual. Many birds are desperately hunting for nest space as trees disappear to make way for human habitation and other purposes.
Building homes in shrubs and tree canopies is tough enough, but species that depend on tree hollows for nest space are facing tough times.
Hollows with just the correct space and size are rare as large old trees are felled for their higher value. And birds are waging a war for nest space on the remaining few.
Dwindling Nest Space Lead To Fight Among Birds
Large birds such as the Cacatua galleria and the sulfur-crested cockatoos need large tree hollows for their nest space. But old trees are the first to go in cities and farms and are becoming ever rarer.
Cockatoos have been seen fighting for a single space, late in winter or early spring. Fights between lorikeets and cockatoos are chaotic and loud. The fight can last minutes but can drag on for more than an hour depending on the quality of the nest space. Things settle down if a pair take possession of the nest space.
The states are particularly great for the Sulphur-crested cockatoos as they are unable to reproduce without a nesting hole. Lorikeets are seen in increasing numbers in southeastern Australia and get into regular fights with the cockatoos for nest space.
The housing fights are loud and have unusual endings. Usually, the lorikeets are driven off by the cockatoos in the fight for a nest space, but eventually, the lorikeets return to the nest if the cockatoos discover that the site is not right for their nesting space. The large hollows are prized but are getting rarer each day.
The hollows are formed from natural causes like a storm or are part of the growth cycle of a tree. Trees continue their growth leaving damaged parts to decay and form into hollow parts. Lightning can also lead to the formation of hollows that are ideal for nest space. Insect attacks can also lead to the hollow formation in tree trunks or branches.
Birds do their bit of interior decoration. Parrots are regularly observed pecking away to get just the right space and feel for their nest space. Cockatoos regularly peck away at large branches at the top of large trees; at the point where the branches meet the main trunk. This causes the formation of holes, that over time decay and form a hollow.
It takes time to transform into a livable nesting space, but cockatoos appear to be long-term investors, ready to wait for seasons before the spots decay into ideal nest space.
Trees Best For Nest Space
The lorikeets, cockatoos, and other species which prefer hollows of trees seem to have a preference for certain species of trees. The sugar gum trees were extensively planted across Australia to serve as windbreaks.
Such trees were lopped to make the top bushier. Such pruning leads to cavities and hollows that make ideal nesting sites, though they weaken the trees.
But sugar gum trees are being brought down in urban areas. Red gums also provide ideal nest space. They grow along rivers and creeks and are huge enough to provide nest space for even large birds in the hollows of their trunks.
The drying up of riverine ecosystems is killing off such trees. Old elms, London planes, and similar trees were regularly lopped, which led to several nesting spaces on each tree. But these trees are being brought down for human settlement.
With the average size of trees becoming smaller, especially in urban and semi-urban areas, large tree cavities are rare and valuable for large birds. It helps retain the biodiversity of a region as even reptiles, mammals, arachnids, and insects shelter in them.
Trees with hollows must be protected, for the nest space they provide for birds like lorikeets and cockatoos.