American Journal of Innovative Research and Applied Sciences. ISSN 2429-5396 I www.american-jiras.com

288

| İbrahim Uysal

* | and | Murat Tosunoğlu

Çanakkale Onsekiz Mart University | Health Services Vocational School | Canakkale | Turkey |

ABSTRACT

Background: Turkey, is one the primary migration bottlenecks in Europe for soaring birds. On the western part of Turkey, on

the other hand, the movement of migration mainly takes place in two bottlenecks where water masses are the narrowest (Bosphorus,

Gallipoli Peninsula-Dardanelles). According to bosphorus, there is a limited number of migration monitoring studies in Gallipoli

Peninsula (Dardanelles). Objectives: The aim of our study is to monitor the migration movements of the Gallipoli peninsula

(Dardanelles) in spring and autumn and to evaluate the relationship between wind intensity and direction of migration intensity.

Methods: Raptor migratory birds were observed during the spring and autumn migration period from 5 point determined on the

Gallipoli peninsula 2015. in A total of 45 days of land work was conducted, 19 days in the autumn migration period (11 August-18

October) and 26 days in the spring migration period (12 March-11 May). Counts were performed following the method described by

Bird & Bildstein (2007). Results: We observed 5296 raptor belonging to 22 species during spring migration period and 3061 raptor

belonging to 20 species during autumn migration period in the field studies. There is a positive (0.464) linear relationship between the

number of individuals observed in the spring migration period and the wind speed (t: 8.089, p: 0.000). 66.6% of the passages were

observed at wind speeds above 20 km / h and 88.5% were observed in the days when the northern winds dominated. In the autumn

migration period, there was no significant relationship between wind speed and number of individuals. It was observed that 69.6% of

the passages occurred on days when the northern winds were dominant. Conclusions: The present study, in 2015, carried out a

reasonably complete census of the raptor birds passing over the Gallipoli peninsula, one of the important migration routes in the

western palearctic region. In this study, it was determined that there is much less passage in the Gallipoli peninsula than in the

Bosphorus. But it was observed that the number of passes increased in the days when strong winds from north and northeastern

dominated.

Keywords

Raptor, Migration, Western Palearctic Region, Bottlenecks, Gallipoli Peninsula, Turkey.

1. INTRODUCTION

It is reported that there are about 10.000 bird species on Earth [1]. In the region Turkey is located within the western

Palearctic distribution shows about 10% of the world's bird species. 2.600 species migrate from at least 141 families of

birds in the world, accounting for about 26.2% of all bird species [2]. Many species perform long-distance migrations

between breeding and non-breeding grounds with tremendous energetic costs, especially when overcoming ecological

barriers such as deserts, water bodies and high mountain chains. For many bird species, the most risky life stage occurs

during migration [3].

Migration is an annual seasonal movement between regular breeding and wintering grounds, covering large geographical

distances over continents, caused primarily by seasonal changes in food abundance [4]. Migration in birds is recognized

as an energetically demanding process due to the long distances covered in flight, thus the flight strategy adopted can

influence survival directly [5]. In order to pass beyond the large sea connections between the continents of Europe and

Africa, birds perform their migration process by centering upon the spots where terrestrial connections are the narrowest.

In particular, the gliding type of migratory birds use thermal air currents so as to be able to complete their migration, and

thermal air currents occur on lands. Broad winged large birds prefer soaring and gliding to flapping flight during

migrations. The fact that while birds during active flying exhausts 23 times higher energy than still flying or

gliding [6]. Thermals are columns of rising warm air that form mainly over the land, but not exclusively. Soaring birds

exploit the uplifting force of the ascending warmer air mass, gaining height by circling up to high altitudes from where

they can glide in their favoured migration direction [7]. For this reason, these tough barriers are very important in

shaping the migration routes of birds.

Since soaring species greatly vary in size and wing shape, differences in their flight behaviour may be explained by bird

size and morphology, as well as different responses to weather conditions such as wind and convective thermal uplifts

ORIGINAL ARTICLE

MIGRATION OF RAPTOR BIRDS ACROSS THE GALLIPOLI

PENINSULA/DARDANALLES, TURKEY

Applied Sciences are the property of Atlantic Center Research Sciences, and is protected by copyright laws CC-BY. See: http://creativecommons.org/licenses/by-nc/4.0/.

American Journal of Innovative Research and Applied Sciences. ISSN 2429-5396 I www.american-jiras.com

289

[8]. Since soaring species greatly vary in size and wing shape, differences in their flight behaviour may be explained by

bird size and morphology, as well as different responses to weather conditions such as wind and convective thermal

uplifts [8]. In particular, eagles and vultures have a lower limit for efficient use of thermals than smaller raptors such as

harriers and falcons. They are also more vulnerable to crosswinds, which cause them to refrain from migration or accept

a drift [9].

Turkey, is one the primary migration bottlenecks in Europe for soaring birds [10]. On the western part of Turkey,

on the other hand, the movement of migration mainly takes place in two bottlenecks where water masses are the

narrowest (Bosphorus, Gallipoli Peninsula/Dardanelles).

Bosphorus (Istanbul) is one of two Bottlenecks in the west of

Turkey. The investigations are concentrated in the Bosphorus. A lot of scientific research have been carried out in

different periods and dates from the Bosphorus [10-17]. A limited number of researches were carried out in the Gallipoli

peninsula/Dardanalles [8, 18, 19].

In western Turkey, there are two narrow constitutes one of the Dardanelles strait is at a critical point in terms of bird

migrations. The wind direction and shape of the coastal area are of great importance for the migration routes of birds.

The winds in northwest (NW) Turkey are predominantly coming from the northeast. This wind drives the birds to the

southwest, a deviation from their theoretical NW-SE route. In this way (in spring) they get more concentrated along the

west coast, especially because most birds hesitate to cross the sea as long as possible. By flying NW (in spring), they

eventually arrive in the area of the Dardanelles, where they can easily cross the narrow straits and don't need to cross

the much wider Sea of Marmara or Egean Sea [18].

The aim of our study is to monitor the migration movements of the Gallipoli peninsula (Dardanelles) in spring and

autumn and to evaluate the relationship between wind intensity and direction of migration intensity. The present study,

in 2015, represents to perform a reasonably complete census of the raptor birds passing over the Gallipoli

peninsula (Dardanelles), one of the important migration routes in the western palearctic region.

2. MATERIALS AND METHODS

The Gallipoli Peninsula direction between the Dardanelles and Saroz Bay. The narrowest area is 5 km (Bolayır) and the

largest region is 25 km. It is connected to Trakya region in northeast part. It extends in a northwest-southeast direction

between the Aegean and Marmara Sea. A large part of the peninsula consists of peaks at different altitudes (the highest

altitude is 420 meters).

Observational studies were carried out at five locations, allowing a large area to be monitored (Figure 1). A total of 45

days of land work was conducted, 19 days in the autumn migration period (11 August-18 October) and 26 days in the

spring migration period (12 March-11 May). Observational studies were carried out between 07:00 and 18:00 hours using

the point count method. Counts were performed following the method described by Bird and Bildstein (2007) [20].

Observations were made using binoculars (magnification 10 ×), spotting scopes (magnification 8-40x 60mm) and

telephoto cameras. All observations were recorded on standard data sheets. Each bird was identified to species level if

possible. When counting individuals one by one became impossible (e.g. rapidly migrating large flocks), individuals were

counted in increments of 10. Wind speed and direction data are taken from the web page of Çanakkale meteorology

general directorate (http://www.mgm.gov.tr/tahmin/il-ve-ilceler.aspx?m= GELIBOLU#sfB).

Figure 1: Coordinates and distribution of observation points.

American Journal of Innovative Research and Applied Sciences. ISSN 2429-5396 I www.american-jiras.com

290

Descriptive statistical analyzes were used in the evaluation of the obtained data. Multiple regression analysis was used to

test the relationship between total daily numbers of raptor species and wind speed and direction. We used the following

variables as independent factors wind direction (categorical variable) and wind speed (km/h).

3. RESULTS

We observed 5296 raptor belonging to 22 species during spring migration period and 3061 raptor belonging to 20 species

during autumn migration period in the field studies. The species with the greatest number of migrants during the spring

migration period were

Clanga pomarina

(52.81 %, 2797 individuals),

Circaetus gallicus

(15.54 %, 823 individuals) and

Buteo buteo

(12.86 %, 681 individuals).