European starlings (Sturnus vulgaris) are a common sight in various environments, ranging from urban areas to agricultural fields and open grasslands. These adaptable birds, originally from Europe, Asia, and North Africa, have successfully spread across much of the globe, including North America, where they were introduced in the late 19th century. Starlings are known for their social nature, often forming large, cohesive flocks.
Distinguishing Physical Features
Identifying male and female starlings involves subtle differences in their appearance, particularly during the breeding season. Both sexes are similar in size, measuring around 20-23 cm in length and weighing between 60-96 grams. Their plumage appears black from a distance, but closer inspection reveals an iridescent sheen with purplish-green hues.
During the breeding season, male starlings exhibit a more vibrant and glossy plumage, appearing somewhat darker due to a richer saturation of their iridescent feathers. Their bills turn a bright yellow, with a distinct blue-ish base. Females, while also having yellow bills during this time, display a pinkish base. This bill color difference is a noticeable indicator.
Beyond bill color and overall sheen, other subtle visual cues differentiate the sexes. Male starlings have longer and more pronounced throat feathers. Females often have shorter, less noticeable throat feathers. While both sexes have dark eyes, males have uniformly dark brown irises, whereas females may have a lighter ring around the outer edge. In non-breeding plumage, both sexes become more heavily speckled with white or buff tips on their feathers, though females may appear more heavily spotted than males.
Behavioral Roles and Courtship
The roles and behaviors of male and female starlings become distinct during the breeding season. Males initiate the breeding process by selecting and defending a nest site, such as a cavity in trees or buildings. They then use elaborate songs and wing-waving displays to attract females.
Once a pair forms, nest building responsibilities are shared. The male usually begins constructing the nest, filling the cavity with materials like twigs, grass, and pine needles. The female then takes over, often refining the structure and lining the nest cup with finer materials such as feathers, leaves, and soft grass. Starlings are generally monogamous, but males may mate with multiple females, providing more care to their primary nest.
Both parents participate in incubating the clutch of 4 to 6 blue-green eggs, which hatch after 12 to 15 days. However, the male’s role in incubation may be smaller, and sometimes males do not sit on the eggs at all. After the young hatch, both the male and female are active in feeding and brooding the nestlings, which remain in the nest for 21 to 23 days before fledging. Fledglings may continue to solicit food from their parents for a few days.
Vocal Differences
Starling vocalizations are complex; both sexes produce calls, but male songs are more elaborate and serve specific functions. Starlings are skilled mimics, capable of incorporating sounds from other birds and even mechanical noises into their songs. This mimicry is a notable aspect of their vocal repertoire.
Male starlings use a variety of calls and songs, including loud whistles and softer, jumbled warbling. Their complex songs, which can last over a minute, are generally directed towards attracting mates and defending their territory. These songs often consist of various phrase types, such as whistles, rattles, and high-frequency sounds. Females also sing, particularly in the fall, but their songs are generally less complex and shorter in duration compared to those of males. Both sexes also use about ten different types of calls for communication related to location, danger, and aggression.