More ornithological studies are being carried out now, but they tend to concentrate on resident birds, and apart from the size of population we still have only limited knowledge about the migrant birds that are part of our global heritage.
我們近來對鳥類的研究已逐漸增加，但多集中在留鳥身上，對屬於國際性資產的候鳥，只有數量調查，生態習性的瞭解仍十分有限。