查看完整版本: what can they be?

what can they be?

先兩個禮拜於南生圍黃昏將近全黑時的行人路邊樹與空地間, 一群小鳥(約2-3吋長), 亂飛和拍翼很密, 能令人錯認是蝴蝶, 牠們在一片小範圍低飛, 很近頭頂, 是在吃昆蟲嗎? 太暗看不出顏色也拍不成照, 又忘了錄下叫聲. 牠們可能是甚麼鳥? 是燕科嗎? 型狀不似雨鳥.

[[i] Last edited by butter at 13/01/2010 14:00 [/i]]

是否文鳥？

Your description reminds me of bats more than birds.3551sweat445

Most certainly bats!  You will need a bat detector to hear or record their calls properly- they are great to watch and listen to.

同意。蝙蝠在我住處附近也有，通常日落前已開始出現。

[quote]Original posted by [i]subbuteo[/i] at 13/01/2010 20:16 [url=http://hkbws.org.hk/BBS/redirect.php?goto=findpost&pid=26881&ptid=10293][img]http://hkbws.org.hk/BBS/images/common/back.gif[/img][/url]
Most certainly bats!  You will need a bat detector to hear or record their calls properly- they are great to watch and listen to. [/quote]
oh, I don't know bats can be this small (only 2-4") ... well, I did hear their call ... short and high-pitched, that's why I knew they're not butterflies. Hmm, I've seen small bats in a tunnel some years ago, those type called like mice. Yet, they're resting when I saw them.

The commonest bat in Hong Kong is Japanese Pipistrelle, and really is as small as you describe (about 5cm or 2"). This is probably the secies you saw. Species like this weigh less than 5g (much less than just about any bird in HK) It always amazes me how tiny bats are! One of the other bat species in Hong Kong (Lesser Yellow Bat) is even smaller, and is one of the smallest mammals in the world.

As subbuteo mentions, listening with a bat detector really opens up a new world at night. Despite being tiny, bats are incredibly loud - but you normally can't hear them because the calls are too high-pitched for human ears. The squeaks you've heard before from roosting bats are used for communication, but they also make continuous high-pitched noises for finding their way when flying at night.

tks for all yr info, pals! By the way, I've come across several of them again just before dark along Kam Tin River on the day of solar eclipse. Last time, I forgot to tell you that its wings looked like an isosceles triangle. This time, I tried very hard to take pics of them but still failed (my arms were sore after lifting my camera for so long)3551em2445

Butter, it's very easy to identify the flying motion of bets.  Bets' flight is not so as steady as birds do and their flight is not a straight line.  In my own words, I will say when a bird flies, you know where it wants to go roughly but for bets you could hardly predict what it will go since the flight is quite circular.  

Also, under traffic light or other similar light sources, the wing section is much more translucent.

Lucky that it's still very common to see bats, since my childhood.  I hope Hong Kong citizens can observe more around their surroundings and understand we always live with nature.  Wild life is not just pests.  They are very interesting indeed. 3551em013445