It’s mid-July now, and I might as well admit defeat at finding the Houston Toad at our Stengl Lost Pines Biological Station this year. It is not unheard of for the species to emerge to mate in some areas even in late July but extremely unlikely. The following log, extracted from my field notes tell the story:
16-02-06: There has been no sign of toad. PS [Phil Schappert] reports sunfish activity at the pond but nothing herpetological.
01-03-06: According to PS, Tom Dureka told him that Mike Forstner has had one confirmed calling this season, another unconfirmed.
20-03-06: Students search Stengl in the evening, 6 p.m. -10 p.m. (PS had suggested that conditions were finally perfect.) Pond and creek. Plenty of sunfish at pond. Some ranids (< 5). No sign of Bufo, no calls at all. Temperature drops to the 50s in the evening—probably the reason.
29-03-06: Stengl has had some rain (Austin has had a lot). PS thinks he heard 2 Houstons calling at 8 p.m.
30-03-06: SS + students search Stengl from 6 p.m. –10 p.m. Plenty of ranids at the pond and the creek, especially R. sphenocephala, chorus + cacophony, starting 7.30 p.m. R. sphenocephala present every few feet all around bank. Sunfish at pond. Explored 3 ponds on southern branch of creek Hyla versicolor + H. cinerea, one individual each. At least two large frogs/ toads that jumped into creek from bank—could not be identified. PS finds Bufo nebulifer at home, below stairs leading to the door. No sign of Houstons at all.
31-03-06: MF [Mike Forstner] says that Houston calls started in earnest last night in Bastrop State Park. Means that the conditions were fine. They just must not have been at Stengl. Chorus started before 10 p.m. Some calls happened as late at 3.45 a.m.
01-04-06: SS + SL [Steve Lanier] at Bastrop State Park lake and Stengl from 4.30 p.m. to 1 a.m. Bastrop: Houston calls unmistakable starting at 7 p.m. Concentrated only toward north-central art of lake. Calls continue till 9 p.m. when we left. Both banks. Probably 6 -10 inds. Couldn’t spot them; calls seem to be from higher ground, not the bank. Very occasional R. sphenocephala call. Stengl: arrived at pond at 9.30 p.m. Occasional signs of R. sphenocephala chorus—few inds. Not one frog on bank. Saw large toad jump into pond—almost certainly B. nebulifer, valley between eyes. Caught one small frog, presumbaly H. versicolor. Strong diff. w.r.t. chorus between 30-03 and 01-04. Diff. atm. conds.: much more overcast, some wind. Also started much later. (On 30-03, chorus was weaker after 9.30.) Sunfish plentiful, juveniles and adults. Will identify from photograph. Creek: partially dredged one pond in southern branch of creek (one toad; four ponds in NE branch. (Northern branch unexplored—need more personnel on ground). R. sphenocephala, juvenile sunfish plentiful. NE branch, fourth pond has H. cinerea. Both species also along banks. No sign of Houston anywhere at Stengl. Is there habitat specificity differentiating Houston and R. sphenocephala?
11-04-06: No sign yet of the Houston Toad at Stengl. PS points out that it has been even drier than it was at the end of March. He’s hopeful about May. We need to find out what the situation is at Griffith League Ranch.
18-04-06: Still no sign according to PS.
26-04-06: There’s been some rain in Austin during the last week but not much at Stengl, about 3/8”, not a “drought breaker” according to PS. He heard crickets on Sunday and Tuesday nights but not frogs.
29-04-06: PS says they had 7/8” rain overnight. This makes more than 2.35” during the last week. This may be our best—and last?—chance to see the toad this season.
30-04-06: Spent a futile night at Bastrop and Stengl. At Bastrop were misled by sound from a cricket which sounded like B. houstonensis. No sign of it at all at Stengl. Students explored the creek—heard one R. sphenocephala but that’s about all the anuran signs we saw.
To top it all, Steve Lanier spent the first two weeks of May at Stengl, staying there every night while taking a field course in ecology from Phil Schappert. There was no sign of Bufo houstonensis.
Presumably the long drought has affected Houston toad populations over the last few years (though there is as yet no sign of a serious population decline in Bastrop State Park). Moreover, there are supposed to be nine other populations of the toad in other counties of Texas, though none as large as the one in Bastrop. However, there is enough reason for worry. Most of us believe that the source of the species’ endangerment—besides, of course, the ubiquitous disappearance of natural habitat, which is continuing today—was the drought of the 1950s which drove the population to low levels from which it has never recovered. A few rough years due to continued climatic instability (presumably because of climate change), may well spell the end of the species. Typically, species respond to climate change by shifting their ranges. But, if the Houston toad is losing out at the eastern end of its range, around Stengl, it will not have this response available. There simply isn’t any adequate habitat left at the western end (or, for that matter, to the north and the south). Lost Pines is it.
Preventing the Houston toad’s extinction may well require far more active intervention, and the sooner that it is done, the better. At the very least, the toad needs better protected habitat than the Bastrop State Park which sees a quite extraordinary level of recreational use. As far as I have been able to make out there are no captive populations of the species today. In the 1980s the Houston Zoo succeeded in growing the species in captivity but that program has been discontinued because of a lack of money. The Zoo made an effort to propagate the toad at the Attwater Prairie Chicken National Wildlife Refuge by releasing 372 506 captive bred toads at different life stages within the Refuge. This Refuge is well-protected and within the historical range of Bufo houstonensis. The efforts were unsuccessful and no one knows exactly why.
Well, I’ll be back next year, and not confine my attention to Stengl. At some point I hope to write a book on this amphibian that has eluded me for so long. All leads will be gratefully acknowledged.