The Northern Mockingbird (Mimus polyglottos) is a widespread bird known for its exceptional vocal abilities. Many observe these birds singing persistently after dusk, raising questions about their nocturnal habits and why they are so vocal when other birds are silent.
Are Mockingbirds Nocturnal?
Northern Mockingbirds are primarily diurnal, meaning they are active during the day. Their main activities, such as foraging and social behaviors, occur between sunrise and sunset. While their nighttime singing can create the impression they are nocturnal, true nocturnal animals are adapted to be active predominantly at night. This characteristic does not apply to the Northern Mockingbird’s overall lifestyle.
Why Mockingbirds Sing at Night
The persistent nighttime singing of Northern Mockingbirds serves several distinct purposes. Unmated males sing extensively at night to attract a mate, especially during breeding season from early spring through summer. This vocal display showcases their health and vigor, signaling their desirability to available females. A male with a larger and more diverse song repertoire, which can include up to 200 different songs, is perceived as more experienced and attractive.
Nighttime singing also plays a role in territorial defense. By vocalizing after dark, male mockingbirds advertise their presence and assert their claim over nesting and foraging territories, warning off rivals. Reduced ambient noise at night allows their songs to travel further and be heard more clearly, making it an effective time to communicate boundaries. Artificial light sources, such as streetlights, can disrupt the birds’ natural circadian rhythms, causing them to extend their singing into the night. They may perceive the light as continued daylight, a phenomenon more common in well-lit urban and suburban areas and more pronounced during full moons.
Mockingbird Daily Behaviors
During daylight hours, Northern Mockingbirds engage in a variety of behaviors. They are omnivores, with their diet shifting seasonally: in spring and summer, they primarily consume insects like beetles, grasshoppers, ants, and wasps, while in fall and winter, their diet consists mainly of berries and fruits. They forage by walking, hopping, or running on the ground, and may also catch insects from perches or hover to snatch hanging fruit.
Northern Mockingbirds are highly territorial year-round, aggressively defending their space from other birds and larger animals, especially during breeding season. They build cup-shaped nests in shrubs or trees, typically 3 to 10 feet off the ground, using twigs, leaves, and other materials, and often raise multiple broods per season. Beyond their own calls, they are renowned for their mimicry, imitating other bird songs, animal sounds like barking dogs, and even artificial noises such as car alarms or sirens.