Starlings are recognized for their iridescent plumage and vocal mimicry. Understanding their breeding habits provides insights into their adaptability. The timing of egg-laying is a key aspect of their reproductive strategy, influenced by environmental cues and biological factors.
The Breeding Season Begins
The egg-laying period for starlings typically begins with spring, extending from March to June. In the United Kingdom, nesting occurs during March and April, while in North America, the breeding period spans from mid-April through mid-July.
The male starling initiates the nesting process by selecting a suitable site, often a cavity in a tree or a man-made structure like a nest box or under roof tiles. He then begins to build the nest using materials such as dried grass and leaves, attracting a mate through song and displays. Once a female chooses a male, she assists in completing the nest, adding finer materials like feathers and moss. Egg-laying usually starts a day or two after nest completion, with the female typically laying one egg each day until the clutch is full.
Influences on Laying Timing
The exact timing of egg-laying for starlings can vary significantly due to several environmental and biological factors. Geographical location plays a role, with birds in southern regions sometimes laying eggs as early as mid-March, while those further north may not begin until mid-April or even mid-June. This latitudinal difference often correlates with the onset of warmer temperatures. Weather conditions, particularly temperature, serve as a significant environmental cue for initiating breeding activities.
Research suggests that warmer long-term temperatures, such as from January through March, can predict and lead to earlier egg-laying. Food availability also influences breeding timing, as sufficient food resources are necessary for the energy demands of egg production and raising young. Social factors, including interactions within a female’s social network, may also fine-tune the timing of egg-laying to local environmental conditions.
Clutch Size and Subsequent Broods
Starlings typically lay a clutch of 4 to 6 eggs, though occasionally up to 7 eggs can be laid. The eggs are glossy and pale blue, without markings. After the clutch is complete, both parents share incubation duties, which usually lasts about 12 to 14 days. Once hatched, the young starlings remain in the nest for approximately 19 to 21 days before fledging, during which time both parents feed them.
Starlings can have multiple broods within a single breeding season, with many pairs raising one to two broods per year. In some instances, they may even produce up to three clutches, particularly if conditions are favorable after successfully raising a first brood. Starlings breeding in southern areas are more likely to have a second brood compared to those in northern regions, where the breeding period is more constrained.