Table 1.

Spatial and temporal patterns of tree cavity occupancy and colony density from 1991 to 2001 based on a 6.25 km² study area and again in 2013 based on a 5.14 km² study area at the Welder Wildlife Refuge, San Patricio County, TX

Year	No. of tree cavities surveyeda	No. of colonies inhabiting tree cavities	Colony density (no./km2)b
1991	10	10	1.6
1992	15	13	2.1
1993	34	30	4.8
1994	70	63	10.1
1995	89	79	12.6
1996	89	32	5.1
1997	89	34	5.4
1998	89	39	6.2
1999	96	61	9.8
2000	111	78	12.5
2001	112	61	9.8
2013	89	28	5.4
1991–2001 average colony density ± SDM			7.3 ± 3.88
1991–2013 average colony density ± SDM			7.1 ± 3.74

^aCavity occupancy data from 1991 to 2001 are reported here as the sum of all established and new colonies inhabiting tree cavities as reported in Table 1 by Pinto et al. (2004).

^bColony density data from 1991 to 2001 are reported similarly to Baum et al. (2005) except that their number of colonies/km² included colonies in tree cavities plus colonies captured in swarm traps, while our data set only includes feral colonies occupying tree cavities as reported also by Pinto et al. (2004).