Adults are slate-grey above with a dark crown and two short black moustachial stripes. The throat is unstreaked white, thighs and undertail coverts are unstreaked rufous and rest of the underparts are whitish with black streaks. Close views enable the red "trousers" and vent to be seen. Sexes are similar. Juveniles are generally much browner, with scaled upper parts and streaked buffy thighs and undertail coverts. The hobby has a distinct first-summer plumage. This falcon is 29–36 cm (11–14 in) in length with a wingspan of 74–84 cm (29–33 in) and a weight of 175–285 g (6.2–10.1 oz). Learn more about Northern Hobby