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Allo-preening is linked to vocal signature development in a wild parrot

Cite this dataset

Berg, Karl; Arellano, Caleb M. M. (2021). Allo-preening is linked to vocal signature development in a wild parrot [Dataset]. Dryad.


Allo-grooming networks in primate social groups are thought to have favored the evolution of vocal recognition systems, including vocal imitation in humans, as a more effective means of maintaining social bonds in large groups. Select avian taxa converged on vocal learning, but it is not clear what role analogues of allo-grooming might have played. Unlike allo-grooming in most primates, allo-preening in birds is usually limited to pair-bonds. One exception to this is during nestling development when siblings preen each other, but it is unknown how allo-preening influences vocal learning. We addressed this question in wild Green-rumped Parrotlets (Forpus passerinus) in Venezuela. Nestlings learn signature contact calls from adult templates. Large broods, age hierarchies and protracted development in this species create the potential for complex allo-preening networks and a unique opportunity to test how early sociality makes the development of vocal learning labile. From audio-video recordings inside nest cavities and a balanced design of different brood sizes, we quantified allo-preening interactions between marked nestlings, to compare to signature contact calls. Controlling for brood size and age hierarchy, the propensity to preen a larger number of individuals (i.e., out-strength) correlated positively with the age at first contact call. Allo-preening and acoustic similarity matrices did not reveal clear correlations within broods, instead larger broods produced greater contact call diversity. Results indicate that allo-preening elongates the period during which contact calls develop, which might allow individuals time to form a unique signature under the computationally challenging social conditions inherent to large groups.


All-preening interactions and age of first contact call were collected from audio-video recordings of parrotlet nesting in Venezuela using Adobe Audition. Hatching dates and hatching sequence within broods were determined from checking nest contents and marking all eggs and nestlings. Sex was determined by noting sexually dichromatic plumage after 15 days post-hatching.

Usage notes

Data from: Allo-preening is linked to vocal signature development in a wild parrot
Variable Definition
Nest Unique code for each nest
VideoName Name of video file
BroodSize Number of nestlings within a brood
Month Month of preening
Day Day of preening
Year Year of preening
Sex_Sender Sex of actor
Sex_Receiver Sex of receiver
AgeSender Age of Actor
AgeReceiver Age of Receiver
AgeDiff Age difference between actor and receiver
Hatseq_Sender Hatch sequence of actor
HatseqReceiver Hatch sequence of reciver
Duration_sec Duration of preening event in seconds
>1sec Observations less than 1 second
>10DPHSender Sender age is greater than 10 days post hatching
<Age1stCCSender Event befor actor had acquired its first contact call
Both Have CC Both actor and receiver have acquired their first contact call


National Science Foundation, Award: 1558145

National Geographic Society, Award: EC0494-11, EC0558-11