# Breeding pairs with color aberrations in oriental reed warblers

## TL;DR

A pair of Oriental reed warblers with unusual white feathers was observed in China, and their breeding behavior was studied for the first time.

## Contribution

This is the first documented case of color aberrations in Oriental reed warblers.

## Key findings

- The color aberrations did not affect the birds' reproductive and antiparasitic behaviors.
- The breeding pair successfully rejected a foreign egg added to their nest.
- The chicks disappeared before fledging, likely due to predation.

## Abstract

In 2017, one pair of Oriental reed warblers (Acrocephalus orientalis) with color aberrations was found in Yongnianwa National Wetland Park, Hebei, China. The female bird exhibited white feathers on the head, neck, and upper back, and the base of the beak was flesh‐red in color. The male had a few feathers on the outer edges of the left and right primary wing coverts that were white, which was determined to be leucism after analysis. The breeding pairs laid their first egg on May 29, with a clutch size of four eggs. After an incubation period of 13 days, two chicks hatched on June 13, 2017. The nest was found empty on June 20 when the chicks were 7 days old and before fledging age; therefore, it was presumed that the chicks had been predated. A white parrot egg was added to the nest during the incubation period to test the egg recognition ability of breeding pairs and was successfully rejected. To the best of our knowledge, this is the first report of color aberrations in the Oriental reed warbler, and we found that this color aberrations did not affect some reproductive and antiparasitic behaviors of the birds, but whether it affects their breeding success needs to be further studied.

One pair of Oriental reed warblers (Acrocephalus orientalis) with color aberrations was found in Yongnianwa National Wetland Park, Hebei, China. This is the first report of color aberrations in the Oriental reed warbler. Color aberrations this color aberrations did not affect some reproductive and antiparasitic behaviors of the birds.