Climate and nest opening orientation in Furnarius rufus (Furnariidae)

Franco L Souza,Cinthia A Santos

doi:10.1590/s0073-47212007000300013

Franco L Souza, Cinthia A Santos

Open Access

https://doi.org/10.1590/s0073-47212007000300013

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Abstract

The Rufous Hornero (Furnarius rufus) is one of the most common bird species in Brazil. Anecdotal information indicates that nest opening orientation in this species is contrary to wind or rainfall direction. To check for the existence of such a pattern, F. rufus nests were randomly sampled within an urban area in central Brazil to assess whether factors such as wind and vegetation cover influence nest opening orientation. Using circular statistics, no evidence was found that nest-opening orientation was important for the species. These results refuse the expected pattern for tree hollow or enclosed nests. The results suggest that factors such as nesting architecture, nest material, nest microclimate or a combination of these, instead of local climate, must be conditioning nesting behavior in this species.

Highlights

Two well-defined climate seasons can be distinguished in this region, a wet summer from November to March and a dry winter from April to October. Due to these distinct seasons a first hypothesis related to F. rufus nesting behavior can be addressed: if F. rufus nest opening is orientated according to local climate, a non-random opening orientation would be expected in Iheringia, Sér
Local climate conditions, mainly wind and rainfall, are the selective factors that could lead species to build their nests in a specific direction (CONNER, 1975; INOUYE, 1976; RAPHAEL, 1985)
The findings reported here are indicative of a case where nesting behavior is not determined by environmental conditions, some interesting approaches concerning nesting behavior of the Furnariidae in general and of F. rufus in particular should be investigated

Summary

Introduction

In spite of the fact that nest architecture is an important feature for systematics and phylogenetic studies in Furnariidae (WHITNEY et al, 1996; ZYSKOWSKI & PRUM, 1999), which in turn can provide interesting insights into nesting behavior among species, studies on this subject are scarce For those bird species nesting in rifts, tree hollows or chambers, such as evidenced for South American Psittacidae (parrots, macaws, parakeets), Picidae (woodpeckers), and Furnariidae (ovenbirds), nest opening orientation usually is related to local environmental conditions. G. inclination) can influence the direction in which birds will positionate the nest entrance (VIÑUELA & SUNYER, 1992; ZWARTJES & NORDELL, 1998; THOGMARTIN, 1999) This relationship between nesting behavior and environmental characteristics is often observed for species from regions with stressing seasonal climatic changes, such as temperate species. Our main goal was to determine which factors drive nest-opening orientation in this species

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