HKBWS BBS 香 港 觀 鳥 會 新 聞 組    Discussion Area 討論區    General 一般問題 (Moderators: Webcreeper, BBS Moderators)    Migratory Bird Day celebrates colonial birds « Previous topic | Next topic » Pages: 1  Reply Send Topic Print    Author  Topic: Migratory Bird Day celebrates colonial birds  (Read 416 times) HKBWS Office BBS Member BBS God     Posts: 1316 Migratory Bird Day celebrates colonial birds « on: May 14th, 2004, 2:39pm » Quote Modify An interesting piece of information from BirdLife International, share with you.   Quote"   Migratory Bird Day celebrates colonial birds 07-05-2004     Communal nesting behavior is being celebrated in the 2004 International Migratory Bird Day (IMBD), being held across the Americas on 8 May.   Nesting in colonies has been a successful strategy evolutionarily for 1 in 8 species of bird worldwide. Many communally-nesting species are water birds, such as frigatebirds, herons, egrets, gulls, terns, and puffins, but several landbirds such as swallows and blackbirds are also colonial. Colony sites take many forms: mud nests plastered on vertical surfaces; burrows riddling a seaside cliff, a stretch of depressions in a sandy beach, or bulky stick nests forming a woodland rookery; what defines them is the close proximity and social behavior of the colony members.     Why do birds gather together to nest? It is believed that coloniality evolved in response to shortages in suitable, safe nesting sites within range of food sources. Birds nesting in colonies may enjoy safety in numbers, for example, when colony members cooperate to chase off predators. Congregatory nesting behavior does have disadvantages though: colonies may actually attract predators, foster higher rates of disease or parasitism, and members may experience increased competition for nest materials and food.     Coloniality also increases population risks by concentrating birds in a limited area. In other words, a single event or incident can affect the nesting success of a large number of birds. There have always been natural threats to colonies such as storms and predators, but human activities have brought many new threats to colonies. The introduction of exotic species to breeding areas, disturbance of colonies, and outright loss of breeding habitat threaten many species of colonial birds.     Fortunately, colonial birds and their colonies are often highly visible and impressive, and thus can garner positive public attention and support. IMBD 2004 will be a chance to celebrate some of the most impressive bird sights in the world.   "Unquote Logged From the HKBWS Office Pages: 1  Reply Send Topic Print Forum Jump: ----------------------------- Announcement 簡訊通告 -----------------------------  - Membership Affair 會員事務   - Outings / Activities 戶外活動 / 講座   - Projects 項目計劃   - Crested Bulbul Club 紅耳鵯俱樂部 ----------------------------- Discussion Area 討論區 -----------------------------=> General 一般問題   - Conservation 自然保育   - Bird Identification 鳥類辨識   - Birding Reports & Tips 觀鳥報告及心得   - Photo Gallery 相片分享 I   - Photo Gallery 相片分享 II ----------------------------- Special Topics 特別主題 -----------------------------  - Wild Birds & Avian Flu 野鳥與禽流感   - Sustainable Management Scheme in Long Valley 塱原可持續生態管理計劃   - Black-faced Spoonbill 黑臉琵鷺   - Goodbye Penfold 告別彭福   - Tern Conservation 燕鷗保育   - Black-eared Kite 鳶(麻鷹)   - Swifts and Swallows 燕與雨燕   - China Birdwatching Network 中國觀鳥活動網絡   - Winter Altas Survey 冬季鳥類普查   - Nature Conservation Policy 自然保育政策 ----------------------------- Knowledge Sharing 知識分享 -----------------------------  - FAQ 常見問題   - Archive 資料重溫 « Previous topic | Next topic »

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