Article Figures & Data
Figures
- Figure 1.
Diagram of an electric transmission ROW divided into a wire zone and 2 border zones. Low-growing tree species and tall shrubs were retained only in border zones.
- Figure 2.
Number of birds per hectare on the ROW for the 6 most common species in July 1982 (pretreatment) and July 1983 (posttreatment). Treatment: HC = handcutting, SB = summer basal, SF = stem-foliage, PE = pellets, FS = frill & squirt. Bird key: YEL = yellowthroat, TOW = towhee, CAT = catbird, INB = indigo bunting, FIS = field sparrow, BLC = blackcapped chickadee, CHW = chestnut-sided warble
- Figure 3.
ROW after handcutting which drastically altered the vegetation structure in the wire zone; shrubs were retained on the borders.
- Figure 4.
ROW after treatment with picloram pellets. A herb-grass-fern cover is in the wire zone; a shrubby border has been retained.
- Figure 5.
ROW after a broadcast stem-foliage spray in the wire zone which is now dominated by hay-scented fern; a shrubby border is on the right
- Figure 6.
ROW after a selective basal spray. Blackberry was retained in both wire and border zones; a grass-herb opening is in the wire zone.
- Figure 7.
Field sparrows perched on a dead tree in the wire zone were the most abundant species on the ROW after treatments.
- Figure 8.
A catbird nest with young on a witch-hazel in the wire zone on a stem-foliage treatment area in 1983 (posttreatment).
Tables
- Table 1.
Number of birds counted per hectare per day on the ROW and in the adjoining forest in July, 1982 (pretreatment) and in June and July, 1983 (post-treatment).
ROW Forest Treatment July 1982 June 1983 July 1983 Change (July) July 1982 June 1983 July 1983 Change (July) No. of birds1 No. of birds1 Handcutting 5.5 5.3 5.0 −0.5 3.0 3.8 2.8 −0.3 Summer basal 6.0 7.3 8.0 + 2.0 3.3 4.8 4.5 + 1.3 Stem-foliage 6.3 5.5 7.5 + 1.0 2.0 2.5 3.3 + 1.3 Pellets 7.3 5.8 6.8 −0.5 3.5 4.3 2.3 −1.3 Frill & squirt 6.3 7.0 8.3 +2.1 2.8 5.0 4.3 + 1.5 Average 6.3 6.3 7.0 +0.7 3.0 4.0 3.5 + 0.5 ↵1 differences in number of birds between treatments were not significant at the 5% level (ANOVA).
- Table 2.
Bird populations in July 1982 (pretreatment) and In 1983 (post-treatment). Abundance (A) = no. of birds counted; % = proportion of total population; rank (R) = rank among all species. Bird names are from Peterson, R. T., 1980.
ROW Forest 1982 July 1983 July 1982 July 1983 July Species A % R A % R A % R A % R Common yellowthroat, Geothlypls trlchas 144 27 1 109 19 2 27 10 3 26 8 4 Rufous-sided towhee, Pipilo erythrophthalmus 75 14 2 63 11 3 47 17 1 57 7 2 Gray catbird, Dumatella carolinensis 51 10 3 53 9 5 1 •1 15 3 1 13 Field sparrow, Spizella pusilla 50 10 4 124 21 1 1 •1 15 2 1 14 Indigo bunting, Passerina cyanea 48 9 5 49 8 6 4 •1 15 5 2 12 Black-capped chickadee, Parus atricapillus 24 5 6 37 6 7 17 6 6 9 3 10 Chestnut-sided warbler, Dendroica pensylvanica 23 4 7 54 9 4 4 2 12 5 2 11 American goldfinch, Carduells tristis 15 3 8 6 1 12 Downy woodpecker, Picoides pubescens 11 2 9 13 2 9 13 5 8 19 6 8 American redstart, Setophaga ruticilla 10 2 10 10 1 11 10 4 10 3 1 13 American robin, Turdus mlgratorius 8 2 11 3 1 14 3 1 13 3 1 13 Brown-headed cowbird, Molothrus ater 7 1 12 5 1 13 Red-eyed vireo, Vireo olivaceus 6 1 12 18 3 8 44 16 2 66 20 1 White-breasted nuthatch, Sitta carolinensis 6 1 13 1 •1 16 12 5 9 25 8 5 Black and white warbler, Mniotilta varia 6 1 13 2 1 15 1 •1 15 Scarlet tanager, Piranga olivacea 5 1 14 15 6 7 6 2 10 Song sparrow, Melospiza melodla 4 1 15 9 2 10 Blue-gray gnatcatcher, Polioptlla caerulea 4 1 15 6 1 12 Rose-breasted grosbeak, Pheucticus ludovlcianus 3 1 16 1 •1 16 2 1 14 1 •1 15 Cedar waxwing, Bombycllla cedrorum 3 1 16 1 •1 16 11 3 9 Great crested flycatcher, Myiarchus crinitus 3 •1 16 3 1 13 3 1 13 Wood thrush, Hyloclchla mustelina 3 •1 16 1 •1 16 22 8 4 19 6 7 Broad-winged hawk, Buteo platypterus 3 1 10 3 1 13 1 •1 15 Black-billed cuckoo, Coccyzus erythropthalmus 2 1 17 Least flycatcher, Empidonax minimus 2 1 17 5 1 13 2 1 14 1 •1 15 Yellow-rumped warbler, Dendroica coronata 2 1 17 Brown creeper, Certhia familiaris 1 •1 18 2 1 14 Canada warbler, Wilsonia canadensis 1 •1 18 American crow, Corvus brachyrhynchos 1 •1 18 2 1 14 Golden-winged warbler, Vermlvora chrysoptera 1 •1 18 2 1 15 Ovenbird, Seiurus aurocapillus 1 •1 18 3 1 14 20 7 5 33 10 3 Ruffed grouse, Bonasa umbellus 1 •1 18 1 •1 15 Great horned owl, Bubo virginianus 1 •1 15 House wren, Troglodytes aedon 2 1 15 1 •1 15 Blue jay, Cyanocitta cristata 1 •1 15 Tufted titmouse, Parus bicolor 3 1 14 Northern raven, Corvus corax Yellow-shafted flicker, Colaptes auratus 2 1 14 Eastern pewee, Contopus virens 1 •1 16 12 5 4 21 7 6 Worm-eating warbler, Helmitheros vermlvorus 1 •1 16 6 2 11 Yellow-billed cuckoo, Coccyzus americanus Black-throated blue warbler, Dendroica caerulescens Northern oriole, Icterus galbula 1 •1 16 Brown thrasher, Toxostoma rufum 2 1 15 Eastern bluebird, Sialia sialis 1 •1 16 Northern cardinal, Cardinalis cardinalis 1 •1 15 Pileated woodpecker, Dryocopus pileatus 2 1 14 Hermit thrush, Catharus guttatus 1 •1 15 Veery, Catharus fuscescens 1 •1 15 Hairy woodpecker, Picoides vlllosus 1 •1 15 Total number 523 586 270 334 No./hectare/day 6.3 7.0 3.0 3.5 No. species (51 total) 32 30 25 30 - Table 3.
Comparison of the total number of birds on 10 sample areas for the 6 most common species in the wire and border zones of the ROW in July, 1983 (post-treatment).
Number of individual birds Species Wire zone Border zone Yellowthroat 55 54 Towhee 35 28 Catbird 27 26 Field sparrow 80a 44a Indigo bunting 24 25 Chestnut-sided warbler 8b 44b ↵a Means followed by the same letter are significantly different from each other at P = 0.05 based on the Wilcoxon sign test for paired observations.
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