Do you enjoy listening to eastern bluebirds (Sialia sialis) in your area and would like to figure out when they sing and why their songs and calls vary so much? Eastern bluebirds are more vocal in parts of the year and their songs and calls vary through the year, with the type of interactions, and even time of the day. In this article, I go over some of the song type variations and seasonality of bluebird songs. There is more to learn than what meets the ear.
Do male and female eastern bluebirds sing?
Typically only the male eastern bluebird sings a diverse array of song types. Females do not usually sing but can give a primary song type, usually when they are in the company of a male or during specific interactions with other bluebirds. Females also use the primary song as a means to warn others about the presence of predators.
The female’s primary song type can also be given by the male and post-fledgling of all ages.
Typical male eastern bluebird song.
Typical female eastern bluebird song.
Male eastern bluebirds have multiple song types
Adult males start with a primary song as a fledgling. Over time, males continue adding notes and phrases to their songs resulting in more complex song types. It is unclear whether birds create their notes and phrases or copy them from other males’ songs.
What is remarkable is that males create new song types throughout a breeding season ending with a more diverse song repertoire at the end of the breeding season than with what they started. As males grow older, their song repertoire grows in complexity. Older and successful males tend to give more complex song types that warn females about the singer’s age, status, and health conditions. Complex song types may increase a male’s chances of being chosen by high quality females.
How diverse can a male bluebird song repertoire be?
Based on bluebird songs’ sonograms, ornithologists have been able to identify 309 different song types. Many may sound similar to a human ear but have different phrases, tones, and combinations only discernible on sonograms.
Ornithologists also noted that song types were unique to each individual and had little overlap with other males’ song types. Of the 309 identified song types given by five males, only six song types were shared by other bluebirds in the group of 5 individuals in the study.
This song type is perhaps the most common across the eastern bluebird range—recording by Paul Marvin –Xeno-Canto.
A song variation that includes elongated notes initially and varies in complexity through the recording -Recording by Chris Parrish –Xeno-Canto.
A rare song variation that includes clear whistles unlike most bluebird songs -recording by Martin St-Michel –Xeno-Canto.
A song variation that is given at dawn. The song includes calls and song types-recording by Paul Driver –Xeno-Canto.
Male song – Florida.
Male song – Connecticut.
Male song – Québec-Canada.
Male song – Pennsylvania.
Loud and soft vocalization types
Eastern bluebird songs can be separated into loud and soft types. The loud song is what we most frequently hear. Loud songs from most bluebirds may sound similar to a human ear.
The soft song type is seldom heard by most observers and is given in a whispering manner. Soft songs are more complex than loud song types.
Bluebirds use loud and soft songs under different circumstances. Loud songs are intended to communicate some type of message to bluebirds at longer distances. The soft song type can be thought of as a whispering chatter typically used when the male and female are in close proximity.
Ornithologists who studied bluebird songs found that most vocalizations (64%) given by a male eastern bluebird are soft. Humans do not hear soft vocalizations unless they are close to the singing bird. A smaller number (21%) of the vocalizations are of the loud type and can be readily heard by humans. The remaining vocalizations (15%) can be considered intermediate and would be heard if one is within a reasonable distance from the singing bird.
During the egg-laying period, males sing soft whispering songs and calls while near the nest. Perhaps reassuring the female of his presence.
What sounds like a female’s primary song is also given by adult males and post-fledgling juveniles.
When do eastern bluebirds sing?
Eastern bluebirds are most vocal early in the nesting season. Males are most vocally active during the pair formation and-egg laying periods, which correspond to March through July. This is the period when males advertise their presence and show their singing prowess to prospective females. During this period, males sing more frequently and, louder, faster, and include a wide variety of song types in their repertoire.
There is a remarkable decline in male vocalization during the incubation, nestling, and post-fledging periods. Males vocalize less frequently and give fewer song types, softer, and at a slower cadence. Bluebirds sing even less after the breeding season.
Males modulate their songs according to the female’s presence
Field studies found that males sang more frequently among mated pairs when a female was perched 10 m or longer from the male. Males vocalized less often when their mate was next to each other and least frequently when she was within 5-10 m.
Frequent vocalizations at distances of 10 m or longer may be intended for the male to keep track of the female without her wandering. While the mated pair is next to each other, Vocalization may be more of a conversational whispering. The least frequent amount of vocalizations when birds are within 5-10 m of each other may be explained by the fact that birds are close enough to keep visual contact, and there is no need to communicate with sounds.
How do bluebirds deliver their songs?
Male bluebirds modulate their behavior according to the time of the year and circumstances. During pair formation, males choose visible perches from where they deliver their loud and more diverse song types. Birds often pivot their body to utter songs in different directions, often accompanied by the tail’s spreading. During the incubation, nestling, and post-fledging, males vocalize from any perch less conspicuously and energetically.
Male and female bluebirds give many different calls associated with interactions between adults, nestling, or fledgling. Adults and nestlings give screeches, chatters, squawks, peeps, and warbles, upon re-encountering, meeting at a perch, entering or leaving the nesting cavity, and warning each other about the presence of competing bluebirds or a predator.
Other types of sounds produced by Eastern bluebirds
Eastern bluebirds make bill snapping sounds, which appear to be linked to circumstances of stress, namely the presence of a predator. Bluebird using bill snapping in an attempt to discourage predators from approaching the nesting site. Bluebirds use the same snapping technique when humans approach an occupied nesting box.
Eastern bluebirds have a diverse portfolio of songs that males accumulate with age. Eastern bluebirds are most vocal during the pair formation and egg-laying periods. Here is when males sing loud songs, more complex, and more frequently to advertise their presence to females.
Bluebirds have loud and soft song types. Loud song types are given by the male while foraging and during activities where some distance separates the male and female. The soft songs are whispering chats that are given when the female is next to the male. Eastern bluebirds have a variety of calls they use during specific interactions and circumstances.
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