Starlings: Habitat, Movements, Feeding & Damage.
Starlings...a prolific pest in agriculture, here are some facts that your may (or may not) want to know.
Starlings are one of the most common species in lowland suburban and cleared agricultural areas of the south east but also occur in open woodlands, irrigated pasture, feedlots, mulga, mallee, reed-beds around wetlands, coastal plains, and occasionally alpine areas. They love hanging out in plant species with dense foliage including Africa boxthorn, firethorn, hawthorn, plane tress, palms, willows, cypress, pines, cedars, oak, and reed beds (e.g. Typha or cumbungi), or concealed cavities in human structures or cliffs. In comparison prominent areas such as powerlines, dead trees, building roofs, and aerials are often used throughout the day for perching and preening
Although starlings will shift regionally movements are generally more localised than nomadic lorikeets and honeyeaters which travel larger distances seeking nectar from flowering plants. In comparison to many migratory populations in northern Europe, starlings in Australia display no large-scale seasonal movements, although distances of up to 2000 km can be flown by individuals dispersing natal colonies. In urban areas they are more sedentary with seasonal fluctuations in abundance due to high juvenile mortality and dispersal. However, small regional movements according to food availability are common, particularly in cultivated and cleared agricultural areas. After sunrise, starlings depart highly aggregated groups of up to 25 000 at roosting sites and disperse in smaller groups to a variety of feeding areas. They usually feed within 2 km from the roost, but can travel up to 80 km in areas of lower food availability. During autumn and winter, they form larger flocks, leave the roost earlier, travel greater distances and have a lower fidelity to particular feeding sites. During these seasons, short-term movements may centre around feeding areas rather than roosting or nesting locations. Hence, when travelling to distant feeding sites, they will often select alternative roosts to minimise necessary travel time. Before returning to the roost at dusk, they regularly gather in large groups often feeding in orchards or grain crops. They also form non-feeding groups in trees, shrubs, buildings, power lines and antenna, where they preen and sing.
Starlings spend over half the day feeding, with the highest proportion of time spent in permanent open grasslands and gardens, preferring those with shorter grass. Other feeding sites vary seasonally and include orchards, vineyards, cereal crops, feedlots and rubbish sites. Feeding duration in cereal and horticultural crops is usually shorter, where large flocks can rapidly remove substantial quantities of fruit and grain. Once a feeding pattern is established starlings will utilise the same foraging sites for extended periods, but unlike other species have no consistent peak feeding times. Starlings feed in large flocks of up to 20 000 which improves their feeding efficiency and decreases losses from predators, such as brown goshawks, collared sparrowhawks, peregrine and brown falcons, swamp harriers, Australian hobbies, barn owls and corvids.
Starlings can cause significant damage to horticultural industries, particularly cherries, grapes, blueberries, olives, stone fruits, apples, pears and a range of vegetable crops. Dried fruit industries are also susceptible with damage evident in currants, sultanas, raisins and dried stone fruits, which occasionally includes birds removing fruit from drying racks. Fruit damage can commence up to six weeks before harvest but increases in frequency during various stages of ripening. Upper branches with sparse vegetation often attract heaviest damage. Whole berries from olives, grapes and cherries are removed and swallowed; larger fruits display a series of sharp peck marks. Cereal crops are susceptible when grain is freshly sown and during ripening. Grain from feedlots, storage areas, piggeries, dairies, poultry farms is often consumed. They can also carry many parasites and diseases which raise concern in food factories and industrial areas and are a potential risk to livestock industries. For example, they are implicated in carrying and in some cases transmitting Salmonella, Cryptococci, Newcastle disease (poultry), transmissible gastroenteritis (pigs), Eastern encephalitis (horses) and foot-and-mouth disease (ungulates), although the risks remain un-quantified.
The Australian government, commissioned this report to The Bureau of Rural Sciences, Department of Agriculture, Fisheries and Forestry in 2003. Images courtesy of Birdway (image1), ABC (image2), Winetitles (image3)