There were once 500 to 600 breeding pairs at the Birecik colony, but the population was dealt a heavy blow when agricultural pesticides were introduced in the 1950 ’ s.
Sekali waktu, ada 500 hingga 600 pasang ibis di koloni Birecik, tetapi banyak sekali yang mati sewaktu pestisida pertanian diperkenalkan pada tahun 1950 - an.