Sea turtle migration Studies of loggerhead and leatherback hatchlings have shown that moonlight reflected from the sea is an important visual cue in guiding movement from the beach to the sea. This navigational mechanism becomes a handicap if nesting sites are affected by artificial lighting since this can mean that hatchlings head towards the artificial lights rather than offshore towards the moonlit sea. Hence, the use of moonlight by turtle hatchings as a navigational cue can be considered an 'evolutionary trap'. Loggerhead and green turtles can detect the orbital movement of waves and use this information to swim perpendicular to the waves crests.
Loggerhead shrike sex an adult loggerhead shrike in the field, as they are sexually monochromatic. However, several studies have reported sexual dimorphism in plumage and size traits. Juveniles possess a paler gray plumage that is subtly vermiculated. The loggerhead shrike can be distinguished from the northern shrike by its smaller size, darker grey plumage and larger black face mask that covers the eye completely. It also has a shorter bill with less prominent hook. Their calls are similar. Their vocal range is broad and varied, and has been described as harsh and jarring. The shrike’s notes include squeaky whistles, shrill trills, guttural