The term 'Spring Singer' refers to two different birds, the ROBIN (5 letters) and the WREN (4 letters). The ROBIN is a small, plump bird with an orange-red breast and a grey back. It is a common sight in gardens and parks throughout Europe, North America, and parts of Asia. The WREN is a small, brown bird with a long tail and a short bill. It is found in woodlands, hedgerows, and gardens across Europe, North America, and parts of Asia. Both birds are known for their beautiful singing voices, which they use to attract mates during the spring breeding season.