Eviction-driven infanticide and sexually selected adoption and infanticide in a neotropical parrot

Infanticide and adoption have been attributed to sexual selection, where an individual later reproduces with the parent whose offspring it killed or adopted. While sexually-selected infanticide is well known, evidence for sexually-selected adoption is anecdotal. We report on both behaviors at 346 nests over 27 years in green-rumped parrotlets (Forpus passerinus) in Venezuela. Parrotlets are monogamous with long-term pairbonds, exhibit a strongly male-biased adult sex ratio, and nest in cavities that are in short supply, creating intense competition for nest sites and mates. Infanticide attacks occurred at 256 nests in two distinct contexts: (1) Attacks were primarily committed by nonbreeding pairs (69%) attempting to evict parents from the cavity. Infanticide attacks per nest were positively correlated with population size and evicting pairs never adopted abandoned offspring. Competition for limited nest sites was a primary cause of eviction-driven infanticide; and (2) Attacks occurred ..., We studied green-rumped parrotlets from 1988-2015 at Hato Masaguaral (8º34' N, 67º35' W), a working cattle ranch 45 km south of Calabozo in the state of Guárico, Venezuela. In 1988 and 1989, 106 identical nest boxes made of 1-m deep polyvinyl chloride tubes with hardware cloth interiors were installed along fence lines in a 4 km2 study area. We monitored an additional 20 nest boxes in some years in a third population 2.5 km from the others. Across the 27-year period of this study (1989-2015), a team of 2-5 field researchers annually monitored the fate of all nesting attempts in boxes. We captured 1512 breeding and nonbreeding adults with mist nets. They were banded with individually identifiable color bands and a numbered metal band, as were all nestlings (n = 7346).
Nest boxes were visited daily every 1-3 days throughout the entire nesting season to determine nest contents and the identities of adults in the vicinity. Data collected from these checks, combined with 2,140 hours of nest ..., , # Data from: Eviction-driven infanticide and sexually selected adoption and infanticide in a neotropical parrot

[https://doi.org/10.5061/dryad.h70rxwds4](https://doi.org/10.5061/dryad.h70rxwds4)

Data sets include:

1\. Mateloss_infanticide.csv

2\. Infanticide_popsize_csv

3\. Rep_male_fitness.csv

## Description of the data and file structure

Data for infanticide attacks and mate loss events at nests of the green-rumped parrotlet (Forpus passerinus) (#1 above), number of attacks annually (#2 above), and fitness of stepfathers (replacement males) at nests with widows (#3 above).

DATA-SPECIFIC INFORMATION FOR: **Mateloss_infanticide.csv**

1\. Number of Variables: 50

2\. Number of Cases: 346

3\. Variable List:

Nest : nest identifier composed of year (first two digits), nest type (1 field, B = box, N = natural), number (identifies the box or natural nest, 1-3 fields), and attempt in the nest (A, B, etc.; 1 field)

Year: year of the nesting attempt

Mateloss: Did one of the pare...