Wing size-related reed habitat selection by Great Reed Warbler (Acrocephalus arundinaceus) males

Abstract

In this study we explored the linkage between wing size of Great Reed Warbler males (Acrocephalus arundinaceus) and their habitat selection and relate these linkages to differences in reed habitat quality. We measured the wing sizes of males nesting in 6 different reed habitats. To explain reed habitat selection, we modeled male wing size as a function of 7 predictor variables describing reedbeds: proportion of managed reed; densities of mixed, old, and fresh reed; reed stem diameter; water depth; and fluctuation of water level. Mean wing size was greatest for males at large canals, intermediate at mining ponds and smaller canals, and lowest at marshes and very small canals. The proportion of managed reed and fluctuation of water level were negatively related to wing size, and water depth was positively related to wing size, which suggests that males with larger wings preferred reed habitats with little management in deep water with little fluctuation in water level. We concluded that the availability of stable, deep water and lack of management are primarily important in attracting larger-winged (presumably dominant) males. Keywords: wing size, reed management, water depth, fluctuation of water level, male, habitat selection, Acrocephalus arundinaceus Selección de há bitat de carrizo con relación al tamaño del ala de machos de Acrocephalus arundinaceus RESUMENEn este estudio exploramos el vínculo entre el tamaño del ala de los machos de Acrocephalus arundinaceus y su selección de hábitat, y relacionamos estos vínculos con diferencias en la calidad del hábitat de carrizo. Medimos el tamaño del ala de machos anidando en seis hábitat diferentes de carrizo. Para explicar la selección del hábitat de carrizo, modelamos el tamaño del ala de los machos como una función de siete variables predictivas de los carrizales: proporción de carrizales con manejo, densidad de carrizo mixto, viejo o nuevo, diámetro del tallo del carrizo, profundidad del agua y fluctuación del nivel del agua. El tamaño medio del ala de los machos fue mayor en los canales grandes, intermedio en los estanques cavados y en los canales más pequeños, y menor en los pantanos y en los canales muy chicos. La proporción de los carrizales con manejo y la fluctuación del nivel del agua estuvieron negativamente relacionadas al tamaño del ala, y la profundidad del agua estuvo positivamente relacionada al tamaño del ala, lo que sugiere que los machos con alas más grandes prefirieron hábitats de carrizo con poco manejo en aguas profundas y con poca fluctuación del nivel del agua. Concluimos que la disponibilidad de agua estable y profunda y la falta de manejo son principalmente importantes para atraer a los machos (presumiblemente dominantes) con alas más grandes. Palabras clave: Acrocephalus arundinaceus, fluctuación del nivel del agua, macho, manejo del carrizo, profundidad del agua, selección de hábitat, tamaño del ala INTRODUCTION

<p class="NoSpacing1">THE EFFECTS OF WEATHER AND REED MANAGEMENT ON NESTING PARAMETERS OF THE GREAT REED WARBLER, ACROCEPHALUS ARUNDINACEUS (AVES: SYLVIIDAE)

“…The importance of water depth for the nesting of the Great Reed Warbler was previously reported as a factor that can characterize the quality of a reed habitat (Graveland 1998, Mérő et al 2016. We confirm the results of previous studies that nest density was related to water depth ; however, Dyrcz (1981) and reported that nest density can also depend on reed structure.…”

Wing-size related habitat choice of Great Reed Warbler females: the role of habitat quality and management

“…In a previous comparison of male wing size over six habitat types (Mérő et al 2016), we found that male wing length was highest along large canals (presumed high-quality habitats), intermediate in mining ponds and middlesized canals, and was lowest in marshes and small canals. We also found evidence that reed (Phragmites australis) habitats attractive to males were those with deep, stable water and little reed management (Mérő et al 2016). Habitat choice by females may correspond to or contradict these patterns.…”

“…Long-winged, probably older, males arrive back to the breeding grounds earlier and occupy territories in the presumably highestquality habitats, and later-arriving, usually younger, males probably settle in habitats of lower quality (Hasselquist 1998, Leisler andSchulze-Hagen 2011). In a previous comparison of male wing size over six habitat types (Mérő et al 2016), we found that male wing length was highest along large canals (presumed high-quality habitats), intermediate in mining ponds and middlesized canals, and was lowest in marshes and small canals. We also found evidence that reed (Phragmites australis) habitats attractive to males were those with deep, stable water and little reed management (Mérő et al 2016).…”

Multi-species habitat models highlight the key importance of flooded reedbeds for inland wetland birds: implications for management and conservation

“…As an example, a very fine-scaled study on Great Reed Warbler in Serbia, found that maintaining different water depth in the reedbed differently affected the survival probability of juveniles, males and females respectively (Méro et al 2018). In the same study site, it has been observed that biggest, putatively dominant, Great Reed Warblers preferentially establish breeding territory in unmanaged (but flooded) portions of the reedbed, while smaller individuals mainly occupy portions of the reedbed in which winter harvesting and burning are practised (Méro et al 2017). The maintenance of a range of different micro-habitats within a reedbed (i.e.…”