The frugivorous white-eared bulbul bird, Pycnonotus leucotis, depredating date fruits: Biology, feeding ecology and management.
Outlooks on Pest Management 29(4):153-157
Abstract:
Date fruits pass through five stages of development; these are the Hababouk (just after fruit setting), Kimri (green small-sized), unripe Khalal or Bisr (50% moisture), ripened Rutab (30-35% moisture), and mature ripened Tamr (10-30% moisture). Birds generally feed on dates during the sweet Khalal, Rutab, and Tamr maturation stages. The most important depredating bird species on date palm fruit are bulbuls, parakeets, house sparrows, crows, and mynas. Bulbuls are by far the most injurious avian pests on date palm in Africa and the Middle East. They are also potential dispersers of noxious weed seeds, besides being vectors and reservoirs for avian diseases and parasites. Bulbuls are mostly used as cage birds where they escape from captivity and establish themselves as feral populations. A good example of populating new areas is the introduction of the white-cheeked bulbul (Pycnonotus leucogenys) into Jordan from Syria and Iraq during 1980s and 1990s as cage birds. There are more than 137 species of bulbul birds worldwide. The genus Pycnonotus comprising 36 species, which are mostly found in Asia and Africa. Of the 36 species of the genus Pycnonotus, 8 species were reported to feed on date fruits. Out of these, 3 are considered serious pests of dates; the common bulbul, Pycnonotus barbatus in Africa, white-cheeked bulbul, P. leucogenys and white-eared bulbul, P. leucotis in Asia. In this article, emphasis was given to the white-eared bulbul due to the large extent of damage in many date producing countries. Information regarding its distribution, biology, feeding ecology, damage to dates, and possible management were highlighted. Date damage by birds was overlooked as no adequate data describing this type of depredation are available. Thus, this article was written with the main objective of giving concise information on bulbul bird damage to date fruits and the possible measures for their management. The white-eared bulbul, Pycnonotus leucotis, is one of the most serious avian pests of date palm. It causes severe depredation on dates that tremendously lowers date quality and results in substantial economic losses. However, the damage to dates inflicted by the bulbuls and their management is overlooked when farmers calculate their production costs. Covering fruit bunches with suitable bags, at the right time of maturation, is the most suitable and practical measure to alleviate bulbul damage on date fruits. In this respect, more research is needed to find cost-effective bunch covers that provide maximum bird protection and least adverse effect on developing date fruits.
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