The descending, joyous twitter of the silvereyes takes on a more sombre note as we go deeper into autumn. The song becomes more melancholy as these little birds switch to winter mode.
The male melody of spring and summer is designed to lure females and declare territory. In autumn and then winter both the male and female silvereyes utter a different call as they strive to keep in contact with each other on the great migration they undertake from Tasmania to southern Queensland.
Although not all the silvereyes make the journey, they still sing the same song as they travel their home range looking for sparse food resources in the cruel Tasmanian winter months.
It is believed only the younger silvereyes make the migratory journey, while mostly older pairs with established territories choose to remain.
The stay-at-home birds form loose flocks as they work their way through shrubbery in winter, feeding on the remaining fruits on trees and gleaning aphids and other bugs from foliage and bark.
Weighing a mere 5-10g and measuring no more than 13 cm, they might be one of the smallest of birds but each year about half the population embark on the 1600 km journey north.
In the winter months Tasmanians holidaymaking on the Gold Coast might well cross paths with the Tasmanian sub-species of silvereye, the Tasmanian birds easily recognisable because they have distinctive plumage. These birds have russet flanks to complement their moss green and grey plumage.
We hear of curlews and albatrosses making epic trans-continental journeys, but for such small birds the flight to Queensland represents one of the greatest feats of avian endurance. Crossing Bass Strait, migratory flocks travel mostly by night, flying high and keeping in contact by uttering that melancholy single-note whistled call. They follow the mainland east coast, replenishing energy as they go with visits to both forests and gardens.
In contrast to the Tasmanian sub-species, most Queensland-born birds are not nomadic, spending winter on the coast before travelling short distances inland to breed.
Breeding begins in August when the travellers return home, and continues through January. In a good season, pairs can raise as many as three broods of two to three young.
Both parents share nest building, incubation and feeding. They weave a small, cup-shaped nest from grass lined with hair and moss, bound together with cobwebs. The young are fed first on insects and later on fruit until they fledge in less than two weeks. Those that survive form permanent pairs in the first winter and may live for 10 years or more.
Because of their small size and unobtrusive nature silvereyes are often overlooked, their spring song being mistaken for that of the descending melody of the scarlet robin. The silvereyes might lack the stunning plumage of the robin, but they grace the garden with their own unspoken beauty.