The Wilson Journal of Ornithology 123(4):741-747, 2011 
A PROBABILISTIC MODEL FOR PRESENCE OF EURASIAN 
NUTHATCH (SITTA EUROPAEA) IN THE ALBORZ MOUNTAINS, 
NORTHERN IRAN 
FATEMEH BAHADORI KHOSROSHAHI, 1 ’ AFSH1N ALIZADEH SHABAN1, 1 
MOHAMMAD KABOL1. 1 MAHMOUD KARAMI. 1 
MURA SHARIATI NAJAFABADI.' AND YOSEFALI AHMADI-MAMAQANI 1 
ABSTRACT.—Hyrcanian forests in the northern Alborz Mountains contain many resident and migrant passerines, but 
the ecological relationships of the species are obscure. We identified the ecological factors (forest structure, type, and 
topography) that could explain the distribution of the Eurasian Nuthatch (Sitta europaea) and its' habitat suitability in this 
region. Significant habitat parameters for presence-absence of Eurasian Nuthatch were height, diameter, stand, and type of 
trees. Our model successfully predicted the presence probability of nuthatches and that suitable habitats strongly depend on 
abundance of old trees, especially Oriental beach (Fagus oriental is) and European hornbeam (Carpinus betulus). These data 
suggest forest structure is the key factor in bird habitat use and suitability, and reveal the necessity of adaptive logging 
activities in Hyrcanian forests. Received 22 June 2010. Accepted If) April 2011. 
Hyrcanian forests in the northern Alborz 
Mountain ranges of northern Iran contain specific 
and distinctive habitats which support a wide 
variety (if fauna and flora. Their vettical distribu¬ 
tions are from sea level to 2.SOI) m asl. These 
forests have high similarity with mixed broadleaf 
forests in central Europe, but are more diverse and 
support more species (Marvi Mohajer 2005). They 
support a significant diversity of bird fauna 
despite the scant distribution of forests in northern 
Iran. Birds in this region are closely related to the 
Western Palaearctic (Majnoniyan et al. 2005). The 
Kheyrud Forest is a part of the Hyrcanian forests 
and supports 50 species from 24 families of birds. 
Most have uniform distribution and belong to 
Passeriformes and Falconiformes. Many birds, 
especially passerines, breed and winter in this 
area, but the ecological relationships of the 
species are obscure, and management strategies 
remain uncertain. 
Habitat suitability modeling has been demon¬ 
strated to be helpful in evaluating w ildlife habitats 
as well as effects of management activities on 
Hahiiat suitability (Austin et al. 1990, Guisan and 
Zimmermann 2000, Barioszewicz el al. 2008). 
The predictive value of habitat models can also be 
used to identify potential areas for species, outside 
°f the region where the model was originally 
developed (Morrison ct al. 1992). General Linear 
Models (GLMs) are frequently used to identify 
Department of Fishery and Environment. Faculty of 
Natural Resources. University of Tehran, Karaj. Iran. 
Corresponding author; e-mail: 
tatemehbahadori 89 @ yahoo.com 
the major habitat factors that explain habitat 
selection by a species in a certain area (Buckland 
and Elston 1993). Habitat selection among 
avifauna operates through a series of behavioral 
decisions al several spatial scales, which explains 
why studying distributional patterns is difficult. 
Habitat selection is a hierarchical process in 
which individuals first select the general area in 
which to live. Within this area they select among 
the available patches for breeding sites (Morrison 
el al. 1992, Pribil and Pieman 1997). 
The Eurasian Nuthatch (Sitta europaea) is an 
area-sensitive species which prefers undisturbed 
old growth forest patches. Our objectives were to: 
(1) examine habitat suitability and (2) identify 
factors that explain the distribution of this species 
in Hyrcanian forests by developing a model that 
could predict the presence of the species with 
acceptable accuracy (Matthysen 1987, Bellamy et 
al. 1998, Gonzalez-Varo et al. 2008). 
METHODS 
Study Area.— The study was conducted in 
Kheyrud Forest (8,000 ha), an educational and 
research forest area, in the Caspian Hyrcanian 
mixed forests of the Alborz Mountains in northern 
Iran (Fig. 1). This area is 7 km east of Nowshahr, 
Mazandaran Province (36 40' to 36 27' N, 
51 43' to 51 22' E). at an elevation of 80 to 
2,200 m asl. The climate of the area is wet with 
cool winters. Annual average precipitation and 
temperature are 1,293.3 mm and 16.1° C, 
respectively (Ahniadi 2006). Dominant plant 
communities include Parrotio-CarpinetHtn. Par- 
rotio-Buxetum, Tilio-Buxetum. Querco-Carpine- 
741 
