藪鳥二重唱接唱重疊與配對年資之關係

Abstract

二重唱是指具有配對關係的兩個個體將各自的鳴唱聲以輪流或交互的方式，形成一個協調有節奏的聲音串，具有共同防衛領域、宣示配對關係的配偶防衛行為等功能。過去研究顯示兩個體間二重唱的協調性可能隨著配對時間的增加而有穩定的趨勢，雙方藉著學習及調整接唱的節奏，表示對於配偶關係的投資，並且辨認、宣示與維持雙方的配對關係；另外二重唱對於其他同種之個體所傳遞意義可能包含個體的品質以及身體狀況，對於其他欲取代配對地位之個體，亦可自訊號中評估入侵的可能以及風險，以減少雙方不必要的衝突與損傷。本研究物種為台灣特有種鳥類藪鳥(Liocichla steerii)，以證實二重唱配合時間會隨配對關係而不同，且可能需要經過練習等投資達到防衛配偶之目的。藪鳥大部分的二重唱是由雄鳥發起，雌鳥回應一至九個音節不等的鳴唱聲所組成。本研究於2006至2008年繁殖季，於台灣南投地區的臺大梅峰農場錄製藪鳥在自然狀態下之二重唱聲音。發現公鳥有固定的鳴唱節奏，而二重唱協調的時間差異是由母鳥控制。在10對配對三年以上及九對當年新形成配對關係之個體間，新配對之二重唱有母鳥對公鳥鳴唱反應時間較短造成雙方鳴唱較多重疊的現象，且母鳥對於公鳥的回應形成二重唱頻度亦較高。因此推測藪鳥的二重唱的確需要母鳥投資能量於鳴唱、辨識公鳥鳴唱聲與練習配合以維繫配對關係，而重疊與否的程度可能代表此配對對外傳達的關係穩定度，也可能是配對內干擾配偶對於吸引異性的訊號傳遞，以維持自身的繁殖地位。

Avian duets are joint acoustic displays by paired individuals, combine their vocal elements with those bouts have a high level of alternation and low variation in the intervals between their elements. Functions of duet include mate guarding, cooperative defense of resource and signal commitment to their partner. The interplay between single components produced by different individuals can form a new quality, so the groups can assess the relative competitive ability of rivals and avoid unnecessary fights. Research shows that the temporal coordination or song structure can be different with pair duration. It may need investment of both of male and female. This research test the coyness hypothesis that female coordinated their songs in different timing with different pairing year. I recorded duet songs of Steere’s Liocichlas (Liocichla steerii) in nature condition, an endemic species in Taiwan in breeding season (March to October) form 2006 to 2008 in NTU farm, Nantou. Male led almost all duets with whistle songs and female follow by 1-9 buzz notes. Result shows male song with a fixed tempo so which the different timing of the song coordination is control by female. Compared the reaction time, intervals and female answer rate between 10 pairs were three year duration and nine pairs were one year. I found that female of new pairs answer their mate more quickly result in more overlap jamming the signal of songs, and female answer rate is higher than old pairs as well. Suggest that it needs to contribute more energy investment for recognizing male songs, adjusting song coordination, and commitment in new pairs. Overlap of songs result from unable anticipate the end of mate’s songs and would come mask the signals of both. It maybe signal that the coalition of pair and the conflict between mate individuals.