Published in HBW Volume 15 on page 489 (above).
Original HBW caption:
Mountain streams and irrigated cultivation provide water for the Yemen Linnet, which is endemic to the Asir Mountains of south-west Saudi Arabia and the highlands of southern and western Yemen. But the die-back of mature trees in some areas indicates that climate change may be resulting in reduced rainfall. Finches in arid environments can meet some of their needs by metabolizing water from their food. Desert populations of the House Finch (Carpodacus mexicanus) in California, USA, have been found to regulate their water use more economically than populations with better access to water.