A Willie Wagtail runs across short grass, pauses with its tail moving sideways, then launches after something too small for you to see. The sequence is often feeding behaviour. Looking for the meal makes the bird more interesting than assigning a human emotion to every tail wag.
A black throat helps with the first identification
The Australian Museum describes a small black-and-white fantail with a black throat, pale chest and belly, a long rounded tail and a conspicuous white eyebrow. BirdLife also points to the eyebrow and pale whisker markings as useful features among similarly sized black-and-white birds.
Adults of the two sexes look similar. A brownish or duller youngster does not establish a female, and an especially active adult does not establish a male. If the throat or face is hidden, keep the identification tentative until more of the bird becomes visible.
The species uses many open habitats, including woodland, parks and sporting grounds. Its presence on a lawn can be natural habitat use rather than evidence that the bird wants people to feed it.
Ground feeding and aerial feeding are connected
The Museum describes foraging from perches and on the ground, with short zigzag runs, tail movements and brief wing flashes associated with flushing small prey from cover. BirdLife describes active ground hunting and aerial insect chases.
Those accounts supply a way to read the sequence without claiming that every tail movement has one experimentally established purpose. Observe whether the bird runs, pauses, chases or returns to a perch. A movement associated with feeding is not proof that a successful capture followed it.
The diet includes many insects, and the Museum also records spiders. When the prey is too small to identify, describing an apparent feeding attempt is more accurate than naming a fly or mosquito from expectation.
A moving animal can provide feeding opportunities
BirdLife describes Willie Wagtails following cattle or sheep to catch disturbed insects. Birds can also use the larger animal as a perch, flying off after prey and returning. The association is about the opportunity to find food; it is not evidence of a friendship in the human sense.
Keep the same distinction when a bird follows activity in a garden. Note where prey might have become available without assuming the bird’s intention is to greet or accompany you. Do not stir vegetation, chase livestock or offer insects to create a demonstration.
The neat cup belongs to a separate part of life
The Museum describes fine grasses and other material bound into a cup with spider webbing, sometimes built on a thin branch or a sheltered structure. Both adults contribute to nesting and care. A bird collecting material is not performing the same task as one catching food, even if both trips end at a nearby branch.
Do not place loose thread, hair or food beside a nest to invite another visit. Leave the structure and its approaches undisturbed. The Museum gives a broad late-winter-to-summer breeding pattern but allows breeding at other times when conditions suit; one calendar does not explain every family.
From a quiet, fixed position, record the date, habitat and sequence of actions you could actually see. Keep uncertainty about prey, age and sex attached to the observation. The restless little bird can reveal plenty without being encouraged to come closer.