Wildwestbirds

Istanbul, the Bosphorus, and Çamlica Hill 40 years on

At the geographical junction of the continents of Europe and Asia, tens of thousands of raptors and storks migrate from the northern to the southern hemisphere over the Bosphorus Strait in September each year.

The first time I witnessed this spectacle was in 1985. The population of Istanbul was 5.5 million at the time. I stayed on the European side of the Bosphorus and took the ferry to Üsküdar. I then walked across open fields, stopping to buy fruit from farmers, as I made my way up to the top of Çamlica Hill, the highest point of elevation along the Bosphorus at 268 meters/879 feet.

In the 40 years since, things have changed dramatically. The current population is around 16 million and Üsküdar's fields are now home to many of the city's residents and the majestic Çamlica Mosque, the largest in Turkey at the crest of Çamlica Hill. Completed in 2019, it can accommodate approximately 63,000 worshippers. Sharing the hill is Çamlica Tower (telecommunication), the tallest structure in Turkey at 369 meters/1,211 feet.

This time I stayed on the Asian side of Istanbul, and after getting over the shock of progress, I soon settled in to my daily routine of making my way through the suburbs up to Çamlica buying fruit from local open air markets along the journey.

The onset of Autumn migration proved quite slow this year, as the ambient temperatures in Europe and Russia were high. The typical start of raptor movement in early September was delayed, but as the mercury dropped mid-month the phenomenon of migration began. Observation from Çamlica Hill on the Asian side of the Bosphorus Strait is still a unique location to watch this spectacle. There are so many choices at varying altitudes making birding quite an active exercise - occasionally even a pain in the neck - and simply knowing where to look an enjoyable challenge!

Large birds, with low wing loading values, are heavy. They need the warm air thermals that develop over land masses warmed by the sun to gain the altitude needed to soar over intercontinental land mass gaps of water. Water forms a physical barrier to aerial migration for heavier birds because it does not produce warm air thermals.

Altitude can be achieved by smaller birds, known as active fliers, because they depend less on air currents to give them the vital lift to reach Africa and Asia. By simply flying directly south and flapping - with many flying at night and adjusting altitude and temperature - they prevent over heating and make the self-powered flight over intercontinental bodies of water.

Looking for vital aid in the form of thermals to lift them over, heavier species funnel down along the western side of the Black Sea's shore following the land mass between the Black Sea and the Sea of Marmara.