Murres - Common and Thick-billed - along with Red-legged and Black-legged Kittiwakes were by far the most abundant breeding birds on St. George Island. There are an estimates 1.7 million
Murres nesting on the cliffs surrounding the island and more than 350,000 Kittiwakes, including 75-80 percent of the world population of Red-legged Kittiwakes. If you click on the image below to enlarge it, you will note the difference between the two species with the middle two birds. The leg color is obvious but the bill size and color of the back are also useful to differentiate them.
The kittiwakes build nest on very small rock outcrops on the cliffs.
They are a little more difficult to tell apart when flying. This is a Black-legged.
When perched on a cliff edge, the red legs of the Red-legged Kittiwakes almost glow in the light.
The juveniles often are found precariously clinging to a rock face.
This Black-legged
Kittiwake has a "
geolocator" attached to one leg. This device records locations of the bird and distances it has flown for feeding and other activities. The bird must be recaptured for the data to be retrieved.
Biologists who monitor and do research on the
Murres told me that they are present in about equal numbers, but most of the
Murres that I took pictures of seemed to be Thick-billed
Murres.
These birds seem to lay their eggs and raise young on almost bare rock ledges. If you click on the image below to enlarge it, you will see a young
Murre on the ledge just to the left and in the shadow of the adult.
The "grin patch" on the bill of a Thick-billed
Murres seems to be the easiest way to tell the species apart. Here you can see it on a flying bird.
The bird in the middle of this image is a Common
Murre with Thick-billed on either side. The Common is a little lighter in color and the bill is shaped differently and without the "grin patch". For the most part, these species seemed to stay together with their own species when perched on the cliffs.
Thick-billed
Murres and Red-legged Kittiwakes were species that I had never seen before. To be able to view them in such large numbers was a treat and just one of the many factors that combined for a great experience on St. George Island of the
Pribilofs!
The kittiwakes build nest on very small rock outcrops on the cliffs. 
They are a little more difficult to tell apart when flying. This is a Black-legged. 
When perched on a cliff edge, the red legs of the Red-legged Kittiwakes almost glow in the light.
The juveniles often are found precariously clinging to a rock face.
This Black-legged Kittiwake has a "geolocator" attached to one leg. This device records locations of the bird and distances it has flown for feeding and other activities. The bird must be recaptured for the data to be retrieved.
Biologists who monitor and do research on the Murres told me that they are present in about equal numbers, but most of the Murres that I took pictures of seemed to be Thick-billed Murres. 
These birds seem to lay their eggs and raise young on almost bare rock ledges. If you click on the image below to enlarge it, you will see a young Murre on the ledge just to the left and in the shadow of the adult. 
The "grin patch" on the bill of a Thick-billed Murres seems to be the easiest way to tell the species apart. Here you can see it on a flying bird. 
The bird in the middle of this image is a Common Murre with Thick-billed on either side. The Common is a little lighter in color and the bill is shaped differently and without the "grin patch". For the most part, these species seemed to stay together with their own species when perched on the cliffs. 
Thick-billed Murres and Red-legged Kittiwakes were species that I had never seen before. To be able to view them in such large numbers was a treat and just one of the many factors that combined for a great experience on St. George Island of the Pribilofs!
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