Introduction to bird identification: winter gulls
Identifying birds in the field and in the lab is an essential skill. If you can learn the basics of gull identification, you can learn to identify virtually any bird. Great Black-backed, Herring, Glaucous, and Iceland Gulls are four common winter species in Newfoundland. The purpose of this part of the lab is to allow you to familiarize yourself with the field marks of these four gull species, and learn to identify these species in the lab from photographs and specimens and later in the field.
Gulls are a challenge to identify because their appearance changes with age. These four large gulls take four years to reach adult plumage. Learn to be confident in identifying the adult plumage first before you proceed to identifying immature birds. Remember, not every bird you see is identifiable, be prepared to conclude "I can't identify this bird". You will need to be able to identify these four species and to age them as first winter, second winter, or adult.
Knowing a bird's age is essential for its identification. If it is mostly pearly gray or slate and white coloured it is an adult. If it is mottled overall with light or dark brown it is an immature.
Wing colour is a basic mark. Two species (Herring and Great Black-backed) have dark wings while the other two (Iceland and Glaucous) are known as white winged gulls because their wings are nearly white.
click to look at some illustrations:
¥ immature white-winged gulls compared
¥ list of all the gull species that winter around St. John's
¥ test yourself on a group of gulls
point out the errors