⅓ of them nest in the region. Over 10% of the birds are endangered. They include Dalmatian pelican and curlew, that are considered to be among the rarest birds in the world. 27 kinds of rare and protected kinds of birds nest in the region, like purple heron. History In antiquity, Claudius Ptolemy called the chain of mountains in which the river rises (northern Pindus) the Canalovii. According to Julius Caesar, the Haliacmon formed the line of demarcation between Macedon and Thessaly. In the upper part of its course it took a southeast direction through Elimiotis, which it watered; and then, continuing to the northeast, formed the boundary between Pieria, Eordaea, and Imathia. In the time of Herodotus the Haliacmon was apparently joined by the Loudias 7, 127, the discharge of the lake of Pella; but a change has taken place in the course of the Loudias, which no longer joins the Haliacmon, but flows directly into the Aegean Sea. The image below shows a wind gap between the Haliacmon and Loudias watersheds that is the probable ancient course of the Haliacmon. It was the domain of the eponymous river god Haliacmon. Gallery References External links Potamoi Rivers of Greece Landforms of Kastoria (regional unit) Rivers of Western Macedonia Landforms of Kozani (regional unit) Landforms of Grevena (regional unit) Landforms of Imathia Landforms of Central Macedonia Landforms of Pieria (regional unit)