=_Mimus polyglottos leucopterus_= (Vigors): Northern Mockingbird.--We recorded this species only near Camp 1, where a few pairs were breeding in stands of mesquite. Males were in full song and territorial display. Specimens (2): [M], 38985, testis 11 × 7 mm., not fat, 43 gm.; [F], 38984, ova to 4.5 mm., vascular brood patch, 49.0 gm.; Camp 1, July 7. PLATE 7 [Illustration: FIG. 1.--Mesquite-cactus formation on clay dune at margin of the Laguna Madre west of Camp 1. Habitat of Northern Mockingbird, Cardinal, Bob-white, black-tailed jackrabbit, and Great Plains woodrat.] [Illustration: FIG. 2.--_Batis-Monanthochloë_ formation on alkaline flats near the Laguna Madre, with mesquite bordering stabilized dunes in the left background. _Salicornia_, a classical dominant of salt marshes, is here relatively inconspicuous. Habitat of Nighthawk and Horned Lark.] PLATE 8 [Illustration: "Fossilized" burrow of Texas Pocket Gopher in a sandy trough between active dunes. A part of the cast has been broken away to show the general shape of the old burrow. The diameter of the cast is about 3.5 inches.] =_Cassidix mexicanus prosopidicola_= Lowery: Great-tailed Grackle.--Small, postbreeding flocks composed of both adult and juvenal birds were seen moving along the edge of the laguna at Camp 1. In the morning the flocks flew south, and in the afternoon groups of similar size flew north, presumably to a roost at an undetermined distance north of our camp. Occasionally, a few birds stopped to rest or to forage on the dunes or in stands of mesquite. At Camp 2 on July 9, a postbreeding adult female and a well-grown, presumably independent juvenile were taken as they perched in a clump of mesquite in which we found three old nests of _Cassidix_; two of the nests were about four feet apart in one tree, and the third was in another tree 100 feet from the first. Specimens (4): [M] adult, 38988, testis 6 mm., no fat, 209 gm., 6 P old, Camp 1, July 7. Female, 38989, ova to 3 mm., fat, 115 gm., old brood patch, Camp 1, July 8. Female, 38990, ova to 1 mm., moderate fat, 107 gm., 7 P old, brood patch refeathering; [M] juv., 38991, testis 3 × 1 mm., not fat, 172 gm., 6 P old; Camp 2, July 9. TABLE 4.--MEASUREMENTS IN MILLIMETERS OF ADULT MALES OF CASSIDIX MEXICANUS