Here's some photos of tracks and signs at La Sal del Rey, USFWS NWR tract. I took these pictures while covering the area on the La Sal Vieja Christmas Bird Count. The salt lake was nearly dry, but was still heavily used for roosting by Sandhill Cranes, Greater White-fronted and Snow Geese. A freshwater spring held the skeleton of a nilgai, an introduced and established ungulate native to India. Nilgai can be more readily observed elsewhere; I've seen more dead animals at La Sal del Rey than live animals. Nilgai are common throughout south Texas.
The skull was partly broken. It was not nearly as heavy or large as a cow skull, but larger and stouter than a white-tailed deer.
Nilgai tracks were all over the lake shore.
Here's the tracks of a coyote on the beach. I watched a pair playing on the sand in the distance. A freshwater spring is the focus of wildlife activity in that saline and arid environment.
The coyote and nilagi tracks were overlapping on the beach. Nilgai are far to large to be prey for the omnivorous coyote, but all the animals were using the spring as a water source. Nilgai use communal feces piles. These are small fecal piles, but the largest I saw on the beach. They are always at the center of a web of tracks of nilgai coming and going. There were a lot more nilgai tracks, with calves skittering and bucking near cows. And yes, I did look up and find some birds, too!