松鸡（学名：Tetrao urogallus），又称西方松鸡，是松鸡科最大的成员，约长100厘米及重4公斤。牠们分布在欧洲北部及亚洲，其求爱方式十分著名。

雄性及雌性松鸡的分别在于其体型及色泽。雄鸡较大，重3.3-6.5公斤，长74-115厘米，双翼展开达1.2米。牠们的羽毛呈深灰色至深褐色，胸部羽毛呈金属深绿色。腹部及后尾视乎品种而呈黑色至白色。

雌鸡较为细小，只有雄鸡约一半的重量，即1.5-2.5公斤。牠们约长54-64厘米，双翼展开约阔70厘米。牠们上身毛色呈褐色，有黑色或银色斑纹，下身呈浅黄色。

The western capercaillie (Tetrao urogallus), also known as the wood grouse, heather cock, or just capercaillie /ˌkæpərˈkeɪli/, is the largest member of the grouse family. The largest known specimen, recorded in captivity, had a weight of 7.2 kg (16 lb). The species shows extreme sexual dimorphism, with the male twice the size of the female. Found across Europe and Asia, this spectacular ground-living forest bird is renowned for its mating display. The United Kingdom population, confined to the pine forests of Scotland, is in rapid decline and threatened with extinction. However, individuals in Northern Europe and Asia number in the millions, and therefore the worldwide population is categorised as "Least concern".