What is the difference between a Caspian tern and a Royal Tern?

Answered by Jarrod Smith

The Caspian Tern and the Royal Tern are two distinct species of birds that can be differentiated by several physical characteristics. One notable difference is their bill size and shape. The Caspian Tern has a heavier bill compared to the Royal Tern, which has a thinner bill. Additionally, the tip of the Caspian Tern’s bill is dusky in color, while the Royal Tern’s bill lacks this dusky tip.

Another distinguishing feature between these two species is their nonbreeding plumage. During the nonbreeding season, the Caspian Tern develops a fuller black cap on its head, while the Royal Tern’s cap remains less pronounced. This difference in the appearance of their head plumage can be useful in identifying the birds, especially when they are not in their breeding plumage.

It is worth noting that these differences are most evident during specific times of the year, as both species have distinct breeding and nonbreeding plumages. During the breeding season, the Caspian Tern displays a black cap with a shaggy crest, while the Royal Tern develops a black cap with a spiky black crest.

In terms of behavior, the Caspian Tern and the Royal Tern may also exhibit some variations. Caspian Terns are known for their strong and direct flight, often flying in a straight line with steady wingbeats. On the other hand, Royal Terns have a more graceful flight, with slower wingbeats and occasional glides.

While these physical and behavioral differences can aid in distinguishing between the two species, it is important to note that individual variations and hybridization can occur, making identification more challenging in some cases. Therefore, it is always helpful to consider multiple characteristics and consult field guides or experienced birdwatchers for accurate identification.

In my personal experience as a bird enthusiast, I have had the opportunity to observe both Caspian Terns and Royal Terns in their natural habitats. It is fascinating to witness the subtle variations in their appearance and behavior, which further emphasize their uniqueness as individual species.