Data on birds and habitat associated with forest management on public conservation areas in the Mississippi Alluvial Valley

This data article contains data collected from 2006–2012 in forests located on 31 State or Federal conservation lands in or adjacent to the Mississippi Alluvial Valley. We present the location, treatment type, and silvicultural age of data collection locations. Presented data on bird detections and forest habitat were collected during avian point counts and associated forest habitat plots and linked to the publication (D.J. Twedt and R.R. Wilson, 2017) [5].


Experimental factors
Forest stands were unharvested control stands or subjected to silvicultural harvests intended to enhance wildlife habitat [3]

Experimental features
Control stands had not been harvested for 420 years and included designated natural areas not subject to harvest. Treated stands were subjected to wildlife forestry silvicultural harvests from 1 to 20 years before data collection. Silvicultural harvests ranged markedly in extent and intensity Data source location Mississippi Alluvial Valley, southern USA Data accessibility Data are provided within this article Value of the data Data provide location, relative intensity of silvicultural treatment, and age of treatment for use in evaluation of the distribution of wildlife forestry treatments.
Categorical time, distance, and species of first detection of each individual bird provide information to evaluate detection probability [4] and detection distance sufficient to enable density estimates that can be compared with avian density estimates from other forest types and under different management.
Forest habitat conditions, including tree species, basal area, and ordinal estimates of vegetative cover, characterize habitat surveyed and which thereby provide benchmarks for bird detections in relation to bottomland hardwood forests of varying structural characteristics.

Data
The data presented herein were collected during avian counts at point locations on public conservation lands in or proximate to the Mississippi Alluvial Valley, within Arkansas, Louisiana, Mississippi, and Tennessee, USA (Supplementary Table 1). Locations were in forests stands subjected to a range of intensity of silvicultural treatments and number of years post-harvest (Fig. 1). The avian dataset (Supplementary Table 2) provides species, distance (within 4 categorical distance radii), and time (within 3 time intervals) of first detection of each identified bird. The habitat dataset (Supplementary Table 3) provides information on categorical vegetation cover as well as species and diameter class of trees that were within 10 BAF (square feet/acre basal area factor) prism plots that were associated with locations of avian counts. Analyses of these data are presented in the associated research article [5].

Study areas
Within each of four states (Arkansas, Louisiana, Mississippi, and Tennessee), we surveyed birds on up to five public conservation management areas (National Wildlife Refuge, Wildlife Management Area, or National Forest) during each year of study (2006)(2007)(2008)(2009)(2010)(2011)(2012). On each public conservation area, our experimental units were forest stands on which silvicultural treatment was prescribed for the entirety of the stand, even if treatment was not uniform throughout the stand. Year of treatment was the year treatment was initiated. Experimental stands were treated within the past 20 years ( Fig. 1), whereas control stands had not been subjected to silvicultural treatment within the past 20 yearstypically not since coming under public management. Local managers subjectively chose control stands with preference for stands of similar forest type to treated stands and included stands designated as natural areas or 'old-growth areas'. Number

Bird surveys
Within each selected forest stand, birds were surveyed at up to six sampling locations that were systematically located 250-meters apart from a random start location and were 4100-m from a primary road or an agricultural edge (Supplementary Table 1). Between 15 May and 30 June, sample locations were surveyed, during clement weather (i.e., no rain or excessive wind) by an experienced observer who recorded bird detection data (Table 1) using a standard field data collection form (Fig. 2). Observers recorded the first detection of each bird within radial distance bands of 0-25 m,  Basal Area of the species within the 10 BAF prism plot (i.e., 10x number of stems 'in' plot) dbh_LT10 Number of trees of the species 'in' the 10 BAF prism plot with diameters at breast height (dbh) that were 4 4 inches and o 10 inches; ( 410 cm-24 cm) dbh_10_20 Number of trees of the species 'in' the 10 BAF prism plot with diameters at breast height (dbh) that were 4 10 inches and o 20 inches; (25-50 cm) dbh_20_30 Number of trees of the species 'in' the 10 BAF prism plot with diameters at breast height (dbh) that were 4 20 inches but o 30 inches; (51-76 cm) dbh_GT30 Number of trees of the species 'in' the 10 BAF prism plot with diameters at breast height (dbh) that were 4 30 inches; ( Table 1).

Habitat surveys
Using variable radius plots based on a 10 (square feet/acre) basal area factor (BAF) prism [1], we assessed habitat at two plots associated with each bird survey location: 1 plot at the point and another at approximately 100 m from the point, except in 2006 when only a single plot was sampled. At each habitat plot, we recorded data using a standard field data collection form (Fig. 3) to record habitat (Table 2) including the species and diameter at breast height of each tree within the 10 BAF plot within four size classes: (10-o25 cm, 25-o 50 cm, 50-76 and 450 cm, and 4 76 cm). We also  Table 3).