查看完整版本: 觀鳥的準備 Preparing for Birdwatching

HKBWS WY 16/11/2009 11:30

觀鳥的準備 Preparing for Birdwatching

[color=Red][size=4][b]觀鳥的準備 Preparing for Birdwatching[/b][/size][/color]


[size=2][size=3][color=Green][u][b]第一步:熟習辨認身邊的雀鳥[/b][/u][/color][/size]
開始觀鳥,最好就是在日常生活中練習辨認身邊出現的野鳥,例如在上學或上班途中,或偶然從窗外眺望。香港到處都有野鳥的蹤影,即使在繁忙的彌敦道上,隨時可以碰上五、六種雀鳥,例如八哥、野鴿、鵲鴝、紅耳鵯、麻雀、珠頸斑鳩等。


[color=Green][size=3][b][u]第二步:配備工具[/u][/b][/size][/color]

[u][b]光學儀器[/b][/u]
一般來說,觀鳥主要的「工具」是我們的眼睛,但假如距離太遠,便需要借助光學儀器把雀鳥放大,以便清楚觀察。

1. [b]雙筒望遠鏡[/b] - 用來觀察飛行中或近距離的雀鳥
一般品牌都會在鏡上刻上一組數字,例如 「10 x 40  7.3 度」,「10 x 40」表示望遠鏡的放大倍數是10倍,物鏡直徑為40毫米;而 「7.3 度」則表示視場(鏡中可見的視野範圍)為7.3 度。

選擇適當的雙筒望遠鏡需要考慮下列因素:
倍數         - 觀鳥用的望遠鏡以7至10倍為佳。倍數太小難以看清楚細節,太大則無法穩定,影像亦較暗。物鏡直徑宜於35至50毫米之間,雖然物鏡越大集光能力越強,但太大則過於笨重,不利長時間使用。
相對亮度 - 相對亮度依[(直徑/倍數)的2次方]公式計算,如10 x 40望遠鏡的相對亮度為16。相對亮度以9至25之間較理想。
鍍膜         - 應選擇有透明鍍膜的望遠鏡。
視場角度 - 適宜在5.5度以上。
鏡身重量 - 觀鳥時望遠鏡掛於頸上,900克以下較為合適。
對焦         - 應選擇手動調焦的望遠鏡,並且以中置對焦為佳。坊間有自動對焦或不用對焦的望遠鏡,不便用來觀察近處的雀鳥。最近對焦距離愈短愈好。
稜鏡         - 傳統折角式稜鏡組合比較簡單,但是體積和重量都比較大。直筒式稜鏡構造緊密,稜鏡和鏡片不易移位,重量也較輕巧。歐洲名牌大都有內置調焦功能,抗潮防塵能力較好,部份更經過充氮防水處理。

2. [b]單筒望遠鏡[/b] - 用來觀察距離遠並且比較不活躍的雀鳥
單筒望遠鏡倍數較高,主要用來觀賞水鳥,因為距離通常較遠。物鏡直徑以60至80毫米為佳。如選用有變焦功能的目鏡,20至60倍變焦較為合適。

3. [b]三腳架[/b]
單筒望遠鏡必須架於三腳架上,三腳架需穩固,負重能力要高,以免在強風中抖動。可選擇有快速收放腳管的設計。

[u][b]圖鑑[/b][/u]
圖鑑幫助我們辨認雀鳥,以及提供鳥類的棲息地點、分佈範圍和行為習性等相關資料。圖鑑分兩種,即攝影圖鑑和手繪圖鑑。除了《香港鳥類圖鑑》及《香港觀鳥手冊》之外,《香港及華南鳥類》也是觀鳥必然之選。

選擇鳥類圖鑑時,應考慮使用環境,如要拿到野外使用,可放在口袋的圖鑑會方便些,可能的話可以選購平裝版本,既實惠又輕便。

[u]
[b]筆記簿、筆[/b][/u]
•        筆記簿宜有硬皮、印有行線、袋裝大小、釘裝結實,另外可加一條橡皮圈作書簽。應使用原子筆,避免用水筆,以免雨水令字跡變得模糊。
•        遇到未能辨認的鳥類,應立即做筆記,記下形態和特徵,然後向資深鳥友請教,或者在香港觀鳥會網上討論區([url]www.hkbws.org.hk/BBS[/url])留言討論,交流經驗。
•        做筆記可以大大提升在野外辨識鳥類的能力。筆記內容愈詳細愈好,包括日期、地點、天氣、鳥類特徵、形態、行為習性、叫聲、種群數量、海拔高度等。


[color=Green][size=3][u][b]第三步:出發時的準備[/b][/u][/size][/color]

避免穿著顏色太鮮艷的服飾,宜選擇綠、啡、藍等配合自然環境的顏色。

不同野鳥有不同的觀察時間,因此應在出發前了解目的地和路線,以便安排行程。觀察林鳥應在清晨時份,觀察海岸附近的濕地水鳥則要注意潮汐時間,宜於大潮前或後到泥灘附近守候。米埔泥灘的理想潮水高度約2.1米左右,尖鼻嘴約為1.4米。觀賞猛禽可選擇中午時份到開闊原野,猛禽會利用從地面上升的熱空氣在空中盤旋。觀察農地或城市鳥類,宜於清晨或黃昏時份,因為雀鳥在中午時不太活躍。海鳥可於夏季時到離岸小島附近海面遠距離觀察,千萬不要登島干擾雀鳥。

鳥種方面,出發前應搜集資料,了解當地的生態環境,配合當時的季節,在圖鑑上查閱可能會遇見的鳥種、辨識要點、常見程度等。準備愈充份,收獲愈豐富。
[/size]

HKBWS WY 16/11/2009 11:44

[color=Red][size=4][b]觀鳥的準備 Preparing for Birdwatching[/b][/size][/color]


[color=Green][u][b][size=3]Step 1: Become Familiar with Birds around You[/size][/b][/u][/color]
To start bird watching, the basic step is to become familiar with birds that can be found around where you live, work or study. This can be practiced while on the way to work or school, or just by looking out of the window. Spotting birds is fun! Birds can be found everywhere in Hong Kong. Even on busy Nathan Road, five or six bird species including Crested Myna, Rock Dove, Magpie Robin, Red-whiskered Bulbul, Tree Sparrow, and Spotted Dove can be easily found within minutes.

[color=Green][size=3][u][b]
Step 2: Get the equipment [/b][/u][/size][/color]

[color=Blue][u][b]Optical Instruments[/b][/u][/color]

Our eyes are the essential “equipment” for bird watching . However, we need optical instruments to watch birds that are too far away for the naked eye.

[b]1. Binoculars[/b] – These are used for watching birds that are not too far away or birds in flight.

Binoculars carry a set of numbers such as 10 x 40  7.3 degree:
-        10 x 40         means the magnification is ten times and the diameter of the objective  lens is 40mm
-        7.3 degree          means the binoculars have a field of view of 7.3

The following specifications are important in selecting a suitable pair of binoculars:
Magnification        -        Binoculars for bird watching normally have 7x to 10x magnification. Lower magnifications can not show enough detail, while higher magnifications can create problems with vibration and a dimmer image. The objective lens should be 35 to 50mm. A bigger lens means more weight and hence not suitable for prolonged use in the field.
Relative brightness        -        Relative brightness can be estimated from the formula [(diameter of the objective lens / magnification)square]. A pair of 10 x 40 binoculars has relative brightness of 16. Values between 9 and 25 are most suitable for bird watching.
Coating        - Binoculars with transparent coatings are preferred.
Field of view        -        It is better to have an angle of view greater than 5.5 degree.
Weight         -        Binoculars will usually be carried around the neck, normally the weight should be below 900g.
Focus        -        Centre-focusing binoculars that focuses both barrels at the same time are preferred. Auto-focus binoculars are not suitable for bird watching. As for shortest focusing distance, the closer the better.
Prism        -        Porro prism designs are more simple. However, inherent from their design, porro prism binoculars are heavier. Roof prism binoculars are compact, light and comfortable to hold. Some roof prism binoculars are nitrogen-filled and are entirely dust-free and waterproof.

[b]2. Telescopes[/b] – Telescopes have much higher magnification than binoculars but a smaller field of view. They are used for watching birds that are relatively inactive from great distances. Objective lenses between 60 and 80mm are preferred. Where used, zoom eyepieces should be from 20x to 60x.

[b]3. Tripod[/b]
A telescope should be placed on a sturdy tripod especially to reduce vibration caused by strong winds. Quick release features on some designs can facilitate deployment.


[color=Blue][b][u]Field Guides[/u][/b][/color]
A good field guide aids field identification, and also gives information on general characteristics such as habitat, distribution and behaviour. They come in two types: photographic guides and drawing guides. In addition, serious birdwatchers in Hong Kong should get a copy of “Birds of Hong Kong and South China” by C.Viney, K. Phillipps and C.Y. Lam, available in both Chinese and English editions.  

Size matters - pocket size is preferred. Perfect-bind is also much better than hard cover, being cheaper and lighter to carry around.

[color=Blue][u][b]Notebook and Pen[/b][/u][/color]
-        It is best to choose a small pocket-size hardcover notebook with lines. A small rubber band can keep it open at the right place, while a ball-pen reduces the risk of ink running when the pages get wet.
-        Use the notebook to take field notes on unfamiliar birds. Then seek help from experienced bird watchers, perhaps by posting your query on the forum of the Hong Kong Bird Watching Society website ([url]www.hkbws.org.hk/BBS[/url]).
-        Field notes should include the following information: date, place, weather, features, behaviour, calls, number, and altitude.


[color=Green][size=3][u][b]Step 3: Preparing for the Trip[/b][/u][/size][/color]

It is always best to try and match the environment, which means wearing suitable colours, especially green, blue and brown. Avoid bright colours.

The best time for bird watching is different in different habitats. If you are going to watch woodland birds, choose early morning when the birds are more active. Viewing wetland birds depends on the tide. Arrive at the bird watching site before or after high tide. The best tidal level for waterbirds at Mai Po boardwalk is about 2.1m, while for Tsim Bei Tsui is about 1.4m. If you are looking for raptors, it is best to go to more open locations around noon, when these birds soar using convection currents. For farmland or urban birds, early morning and late afternoon are the best time. Birds are generally not too active around noon. For seabirds, we need to go to remote islands during summer. Good views can be obtained from a boat. It is not necessary to land on the islands, and doing so disturbs the birds.

To prepare for a successful outing, it is good to collect information on habitat and season, and to search the field guide for information on possible species, their identification and abundance. Good preparation leads to more impressive and productive trips.
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