Well, I can't say that they seemed particularly associated with water. Only the first one was found near any sort of body of water. Two others were found on in a grapefruit orchard we herped in(that'd be the big female and the juvie), which I suppose got watered via irrigation, but I didn't see any standing water. We also found one within a mile of a small stretch of swampland. 3 of them were found on roads (all alive, no DOR thank god). Several were found in the Chaparral Wildlife Management area; we were with a school group so had permits to go in there.
The northernmost one (the first one) was found in Uvalde County, on a private ranch, but we did see them as far south as Brownsville--that's were the last one, which was found near a swamp was.
Of the ones we found; 3 were on roads basking, one was on the prowl near the water, the baby was hiding in some leaf litter in the orchard, the large female was up a tree in the same orchard. The ones in the chaparral area were all found active and prowling (two in morning, one after dark).
Most of them were found early morning through noonish, although we did find one after dark--that was in the chaparral. In terms of prey? I couldn't say, we didn't take samples of that (although we did with diamondbacks in the same area, one of the guys was a master student working on a thesis regarding their prey). We found tons of potential prey animals--IIRC, we documented over 200 bird species and in the dozens of small to mid sized mammals in the area. There were also an abundance of midsized lizards and rodents (particularly wood rats) in the same area as the Uvalde county one, although we couldn't find much else in the way of snakes there.
In the place in Uvalde county, we found lots of Sceloporus, as well as a fair amount of neotenes salamanders near that river the snake was in. there were goodly amounts of fish in said river, but I couldn't tell you species. We didn't find any other snakes right near it, but on the same ranch we found variety of small fossorial species of snakes--H. torguata, Diadiophis, Tantilla. There were many, many small skinks--tetragammus mostly. We also found sirens on that ranch, in a seasonal pond--that was even better than the indigo! There weren't any other large snake species that we found there, but then, the weather was iffy. I'd kill to go back during better herping weather.
Down south, in the Chaparral area, we found C. atrox in abundance (including a phenomenal 5.5' male with the most amazing pattern--I really wanted to bring that one home) T. gracilis R. lecontei (several), P. sayi (also in abundance) and A. elegans. We found a Thamnophis too--a very pretty one--that had been partially eaten by something. There weren't as many lizards but there were still some whiptails and of course scelops. We found only one skink there--another tetragammus.
The one in the swamp, well, alligators, thamnophis, and that was mostly it. The time at the swamp wasn't productive; it was coolish, and overcast and stuff was mostly inactive. Tons of chacalaca's and green jays, and crested caracara's though.
In the orchard--blind snakes, Laredo whiptails, one atrox, many skinks, more tantillas, a lyre snake. Not many herps out that day, but not too bad--and the grapefruit was freaking good.
I can't even start to list the bird and mammal life we found. Or insect/arachnid either--although I did find a solfugid (and nearly got bitten) while looking for reticulated collared lizards. We did find Texas banded geckos though, which was a real treat.
I'm hoping, if gas prices stay down, to go on another south texas camping/herping trip this summer. I won't be part of a group so some of the really cool areas will be off limits, but I have family throughout south texas so I can get to *some* places. On that trip these photos are from I got a *lot* of lifers--sirens, indigo's, lyre snakes, as well as some raptor species. I've also found buttermilk racers, although that was separate, in the same area (birdwatching with family on a trip down).
Oh and we found some texas tortise, although those weren't near indigo's--they were just awesome in thier own right.