|Most recent IBA monitoring assessment|
|Year of assessment||Threat score (pressure)||Condition score (state)||Action score (response)|
|2016||very high||very unfavourable||medium|
|For more information about IBA monitoring please click here|
The Boðaziçi strait runs north-south for c.33 km, and is c.1.5 km wide. The site includes the forested areas east (Polonezköy Nature Park) and west (Belgrade forest) of the strait, which are known to be of importance to roosting migrants. It does not include the çamlýca hills and the islands in the Sea of Marmara, which would qualify as an IBA in their own right due to the large numbers of migrants passing over, but which provide limited scope for bird conservation.
The site is a major migratory bottleneck, where more than 20,000 storks and raptors regularly pass in spring and autumn. Few counts covering the entire migration period have been undertaken. Total counts made in the mid-1960s and early 1970s and covering the entire autumn migration period are as follows: Ciconia nigra (8,318), Ciconia ciconia (338,353), Pernis apivorus (25,751), Milvus migrans (2,707), Buteo buteo (32,895) and Aquila pomarina (18,898). More recent autumn records include 11,703 Aquila pomarina at çamlýca and 11,379 of the same species at Sarýyer, both on the same day in September 1990. Ciconia sp. often roost in flocks of thousands in fields outside the city. Disturbance by Larus cachinnans and possibly pollution are thought to be behind a drastic decline in numbers of breeding Milvus migrans.
BirdLife International (2017) Important Bird Areas factsheet: Bosphorus. Downloaded from http://www.birdlife.org on 22/11/2017.