In my last post, I wrote about Whooping Cranes and the trip I took to see them at the Aransas National Wildlife Refuge. The Whooping Cranes were the highlight of that trip, but the refuge is home to many other bird species. Here are a few pictures of birds and other wildlife at the refuge:
Both species of pelican that occur in North America were quite common in the area. The smaller Brown Pelicans are coastal species and occur in the area year-round and breed there. American White Pelicans, however, are generally migratory, although there are populations in Texas and Mexico that do not migrate.
These two pelican species have different foraging styles. Brown Pelicans will dive for their food, and I frequently saw them dive straight into the water from the air. American White Pelicans do not dive like that and scoop prey from the water. They will also steal food from other species, especially cormorants.
The above picture shows three adult and one juvenile Brown Pelican. The dark brown bird is the juvenile. Note also the white necks on the adults. Adult Brown Pelicans have white necks when they are not breeding, while during the breeding season, the backs of their necks will be dark brown.
The black bird in above picture is a Neotropical Cormorant. Cormorants are frequently seen in the company of pelicans and both Neotropical and Double-crested Cormorants occur on the south Texas coast. These two cormorant species are not always easy to differentiate, although the neotropicals are smaller, have shorter beaks, and have longer tails. The shape of the gular (throat) pouch also differs between the two species.
I actually took the above photo in Lethbridge, Alberta, but it shows one structural difference between breeding and non-breeding American White Pelicans. During the early breeding season, American White Pelicans develop a round, horny disk on the top mandible of the beak. This is lost after the breeding season.
I managed to see quite a few “lifer” birds on the trip, as I’d never been to the east coast. A “lifer” would be a bird that I had never seen before. The Gull-billed Tern (seen in the above photo) and the Neotropical Cormorant were lifers for me. It’s always exciting to see a see a new species, and ever better for me if I can get a decent picture.
Osprey were very common, but I also managed to see a Peregrine Falcon. Peregrines are well-known for having the fastest dive speed among birds, as they can reach speeds of 320 km/hour during a dive. The species was considered endangered in the United States during the mid twentieth century, and population declines were largely due to the use of organochlorine pesticides (primarily DDT). These pesticides caused females to lay eggs with thin shells. The species has since made a recovery due to DDT bans and the release of captive-bred birds.
Shorebirds are abundant on the gulf coast during winter, as many species that breed further north overwinter there. Shown above is a Ruddy Turnstone. They spend the winters on the Atlantic and Pacific coasts of the USA and breed in the high Arctic. Their breeding plumage is much sharper than their winter plumage.
Willets (one is shown above) are medium shorebirds that overwinter on the Atlantic and Pacific coasts and breed on the north Atlantic coast and inland in central Canada and the northwestern USA. They are rather plain shorebirds, but in flight, they are easy to recognize due to the sharp, black and white striped patterns they have on the undersides of their wings.
Herons were also quite common, and the above photo shows a Snowy Egret (which is in the heron family). Cattle Egrets, Great Egrets, and Reddish Egrets also occur in the area.
Dolphins were also quite common and often swam beside or behind the boat. I also saw several dolphins while on a boat trip off of South Padre Island.
I took the photo of the above bird (a Long-billed Curlew) in a field between Harlingen and Corpus Christi. A very large flock of curlews was foraging in the field. Long-billed Curlews often forage for worms in pastures and their long bills help them probe deep into mud. On coasts, where some birds overwinter, they will forage for shrimp and crabs and can often reach them in their mud burrows.
A Ferruginous Hawk and Sprague’s Pipit were also present alongside the curlews. These three species are declining in Canada (the Ferruginous Hawk is particularly scarce), so seeing all of them in one spot was quite thrilling for me. I couldn’t get a decent picture of the hawk (it was too far away), but here’s a photo of one I took near Mountain View, Alberta.
The Texas pictures were all taken with a Panasonic Lumix DMC-FZ70 camera. It has a 60X zoom lens, so I didn’t have to get too close to the birds to get decent pictures.