Clark's nutcracker (Nucifraga columbiana), sometimes referred to as Clark's crow or woodpecker crow, is a passerine bird in the family Corvidae, native to the mountains of western North America. The bird was described by the Lewis and Clark Expedition, with William Clark first observing it in 1805 along the banks of the Salmon River, a tributary of the Columbia River. Clark's nutcracker is mainly found in mountains at altitudes of 3,000–12,900 ft in conifer forest. It is not typically migratory, but does seasonally move between higher elevations in the summer breeding season and lower elevations in the winter. Some populations will remain year-round at high elevations if they have sufficient food caches. The staple food of a Clark Nutcracker’s diet is pine seeds. They bury seeds in the ground in the summer and then retrieve them in the winter by memory. Clark’s Nutcrackers are gregarious birds that typically travel in small flocks, calling back and forth with far-carrying, rolling calls. I saw them at Crater Lake NP, Oregon and Lassen Volcanic NP, California. I saw it because I heard its cry.
北美星鴉有時也被稱為克拉克烏鴉或啄木鳥烏鴉，是鴉科的一種雀形目鳥類，原產於北美西部的山區。這種鳥是由劉易斯和克拉克探險隊描述的，威廉克拉克於 1805 年在哥倫比亞河支流薩蒙河沿岸首次觀察到它。北美星鴉主要分佈在海拔 3000 至 12,900 英尺的針葉林。它們通常不遷徙，但會在夏季繁殖季節遷徙到高海拔地區，冬季則遷移到低海拔地區。如果食物儲備充足，有些族群會常年居住在高海拔地區。北美星鴉的主食是松子。它們在夏天將種子埋在地下，然後在冬天憑記憶取回。北美星鴉是一種群居鳥類，通常小群遷徙，用連連傳播範圍很廣的鳴叫聲來回傳叫。我在俄勒岡州的火山口湖國家公園和加州的拉森火山國家公園看到了它們。我是因聽到它的叫聲而看到它。
Notes 筆記
- Clark's nutcracker (Nucifraga columbiana), sometimes referred to as Clark's crow or woodpecker crow, is a passerine bird in the family Corvidae, native to the mountains of western North America. Clark's nutcracker's scientific name literally means "nutcracker of the Columbia". The bird was described by the Lewis and Clark Expedition, with William Clark first observing it in 1805 along the banks of the Salmon River, a tributary of the Columbia River.
- Clark's nutcracker is mainly found in mountains at altitudes of 3,000–12,900 ft in conifer forest. It is not typically migratory, but does seasonally move between higher elevations in the summer breeding season and lower elevations in the winter. Some populations will remain year-round at high elevations if they have sufficient food caches.
- The nutcracker is an omnivore, but consists mainly of pine nuts, burying seeds in the ground in the summer and then retrieving them in the winter by memory. Clark's nutcrackers store seeds, usually in the ground for later consumption. They favor cache sites on steep, south-facing mountain slopes, as snow will melt here earliest in the year. Depending on the cone crop as well as the tree species, a single Clark's nutcracker can cache as many as 98,000 seeds per season. The birds regularly store more than they actually need as insurance against seed theft by other animals (squirrels, etc.), as well as low availability of alternative foods; this surplus seed is left in the cache, and may be able to germinate and grow into new trees. This storage behavior allows demonstration of the bird's long-term spatial memory; they are able to relocate caches of seeds with great accuracy up to nine months after initial storage. Clark's nutcrackers are heavily dependent on food retrieved from caches throughout the winter, and will dig up caches, even when buried under heavy snow. Short-term pictoral memory tasks reveal that while nutcrackers have particularly adept spatial memories, their visual memory is unremarkable; the cognitive ability they use to recover caches appears to be specifically evolved for this purpose.
- Clark's nutcrackers, like other Corvids, are opportunistic feeders whose diet also includes a wide range of insect prey, rodents, nestling birds and eggs, amphibians, and carrion.
- The species usually nests in pines or other types of conifers during early spring. Two to six eggs are laid per nest, with incubation occurring over approximately 18 days. Incubation is performed by both the male and female parents.
- Clark's nutcracker is the primary seed disperser for whitebark pine (Pinus albicaulis).
- Clark’s Nutcrackers are gregarious birds that typically travel in small flocks, calling back and forth with far-carrying, rolling calls.
- The nutcrackers are almost always in groups, except while depositing or retrieving seed caches.
- Clark’s Nutcrackers are monogamous and pair bonds seem to last for many years, although this hasn’t been studied closely enough to be certain.
- Courting birds fly together with fast dives and swoops, feed each other, and may hold twigs in their bills. Pairs hold nesting territories, which they may defend by locking bills and claws with intruders.
- 北美星鴉有時也被稱為克拉克烏鴉或啄木鳥烏鴉，是鴉科的一種雀形目鳥類，原產於北美西部的山區。這種鳥是由劉易斯和克拉克探險隊描述的，威廉克拉克於 1805 年在哥倫比亞河支流薩蒙河沿岸首次觀察到它。
- 北美星鴉主要分佈在海拔 3000 至 12,900 英尺的針葉林。它們通常不遷徙，但會在夏季繁殖季節遷徙到高海拔地區，冬季則遷移到低海拔地區。如果食物儲備充足，有些族群會常年居住在高海拔地區。
- 北美星鴉是雜食動物，但主要以松子為食，夏天將種子埋在地下，然後在冬天憑記憶取回。北美星鴉通常會將種子儲存在地下，以備日後食用。它們喜歡在陡峭的南向山坡上尋找藏匿地點，因為這裡的積雪一年中最早融化。根據球果作物和樹種的不同，一隻北美星鴉每季可以儲存多達 98,000 顆種子。為了防止其他動物（例如松鼠）偷竊種子，以及替代食物供應不足，它們通常會儲存比實際所需更多的種子；這些多餘的種子會被留在藏匿處，或許能夠發芽長成新樹。這種儲存行為展現了鳥類的長期空間記憶；它們能夠在最初儲存的種子九個月後，仍然能夠非常準確地重新定位藏匿的種子。北美星鴉在整個冬季都高度依賴從藏匿處獲取的食物，即使被大雪掩埋，它們也會挖出藏匿處的食物。短期圖像記憶任務表明，雖然北美星鴉具有特別熟練的空間記憶，但它們的視覺記憶卻並不出色；它們用來恢復緩存的認知能力似乎是專門為此目的而進化的。
- 與其他鴉科鳥類一樣，北美星鴉是機會主義的覓食者，其食物還包括各種昆蟲獵物、囓齒動物、雛鳥和鳥蛋、兩棲動物和腐屍。
- 北美星鴉通常在早春時節在松樹或其他針葉樹上築巢。每巢產卵 2 至 6 枚，孵化期約 18 天。孵化由雌雄雙方共同完成。
- 北美星鴉是白皮松的主要種子傳播者。
- 北美星鴉是一種群居鳥類，通常成小群遷徙，用連連傳播範圍很廣的鳴叫聲來回傳叫。
- 除了存放或取回種子儲藏的時候，北美星鴉幾乎總是成群結隊。
- 北美星鴉是一夫一妻制的鳥類，配偶關係似乎能維持很多年，雖然這一點尚未得到深入研究，無法確定。
- 求偶的鳥類會一起飛行，快速俯衝，互相餵食，並可能用喙銜住樹枝。雌雄鳥會佔據築巢領地，它們可能會用喙和爪子與入侵者搏鬥來保衛領地。
References 參考資料
- Wikipedia: Clark's nutcracker
- All about birds: Clark's Nutcracker
- National Park Service: Clark’s Nutcracker
- 維基百科: 北美星鴉
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