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Pipilo erythrophthalmus

• INTRODUCTORY
• WILDLIFE DISTRIBUTION AND OCCURRENCE
• BIOLOGICAL DATA AND HABITAT REQUIREMENTS
• FIRE EFFECTS AND USE
• REFERENCES

INTRODUCTORY

AUTHORSHIP AND CITATION FEIS ABBREVIATION SYNONYMS COMMON NAMES TAXONOMY ORDER CLASS FEDERAL LEGAL STATUS OTHER STATUS
	Will Cook, www.carolinanature.com

AUTHORSHIP AND CITATION:
Meyer, Rachelle. 2006. Pipilo erythrophthalmus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: www.fs.usda.gov/database/feis/animals/bird/pier/all.html [].

FEIS ABBREVIATION:
PIER

SYNONYMS:
None

COMMON NAME: [3]
eastern towhee

TAXONOMY:
Pipilo erythrophthalmus (Linnaeus) is the scientific name for eastern towhee, a member of the Emberizidae family [3]. In 1995, the American Ornithologists' Union split the rufous-sided towhee (P. erythrophthalmus) into the eastern and spotted towhee (P. maculatus) [2]. Hybridization between the 2 species occurs along riparian corridors in the Great Plains, especially on the Platte River [42,82]. The 4 eastern towhee subspecies recognized by the American Ornithological Union [1] are:

P. e. ssp. erythrophthalmus (Linnaeus)
P. e. ssp. alleni Coues
P. e. ssp. canaster Howell
P. e. ssp. rileyi Koelz

ORDER:
Passeriformes

CLASS:
Bird

FEDERAL LEGAL STATUS:
No special status

OTHER STATUS:
None

WILDLIFE DISTRIBUTION AND OCCURRENCE

• GENERAL DISTRIBUTION
• ECOSYSTEMS
• STATES/PROVINCES
• BLM PHYSIOGRAPHIC REGIONS
• KUCHLER PLANT ASSOCIATIONS
• SAF COVER TYPES
• SRM (RANGELAND) COVER TYPES
• PLANT COMMUNITIES

Pipilo e. erythrophthalmus occurs in the most northerly part of the eastern towhee's distribution in the summer, and migrates to the southern and eastern portion of the species' range in the winter. The other subspecies are largely residents [69]. Pipilo e. canaster occurs from south-central Louisiana, north to northeastern Louisiana east through Mississippi, extreme southwestern Tennessee, northern Alabama and Georgia, central South Carolina to western North Carolina, and south to northwestern Florida and east along the Gulf Coast [1]. The range of P. e. rileyi extends from northern Florida through southern Georgia and coastal South Carolina to east-central North Carolina. Pipilo e. alleni occurs in peninsular Florida [69].

The following lists are based on eastern towhee distribution information and the habitat characteristics and plant species composition of vegetation communities eastern towhees are known to occupy. There is not conclusive evidence that eastern towhees occur in all the habitat types listed, and some community types, especially those in the western portion of the eastern towhee's range, may have been omitted. Abundance of eastern towhees in the community types listed is quite variable. Some plant communities support eastern towhees only in stands of specific ages or types, while others provide suitable habitat throughout. See Preferred Habitat/Cover for more detail.

BIOLOGICAL DATA AND HABITAT REQUIREMENTS

SPECIES: Pipilo erythrophthalmus

TIMING OF MAJOR LIFE HISTORY EVENTS PREFERRED HABITAT COVER REQUIREMENTS FOOD HABITS PREDATORS MANAGEMENT CONSIDERATIONS
	G. K. Peck, Environment Canada

Breeding begins in spring and continues to late summer. Reports of eastern towhees nesting as early as late March in Florida and Georgia, in mid- to late April in some midwestern states, and as late as mid-May in northern New England were summarized in a literature review [42]. Literature reviews also report nest construction by the female, which takes about 3 to 5 days [34,42]. Egg laying typically occurs until August. For example, a review of eastern towhee in Indiana notes nesting from 15 April to 20 August [67]. However, a literature review of eastern towhee in Florida included a report of an eastern towhee nest observed on 2 September 1983 that contained 2 eggs [86]. According to several literature reviews, eastern towhees may renest after failed nesting attempts and can raise 2, and in the south sometimes 3, broods per season [34,42,86].

In a literature review, Greenlaw [42] reports mean breeding territory size of 4 acres (1.6 ha) (range 1.6-6 acres (0.64-2.44 ha), n=24) in a mesic oak (Quercus spp.) forest where eastern towhees occurred at a density of 21 males/40 ha. In a xeric pine (Pinus spp.)-oak woodland where eastern towhee density was 32 males/40 ha, mean eastern towhee territory size was 3 acres (1.2 ha) (range 1.8-4 acres (0.71-1.65 ha), n=20) [42]. In Massachusetts, mean male eastern towhee territory size was about 1.3 acres (0.52 ha), and female eastern towhee territory size was 1.1 acres (0.45 ha). Territory size changed over the course of the breeding season and was not significantly (p>0.05) affected by reductions in food availability of 30% or less [97]. During the winter eastern towhees are not as territorial and may be seen in mixed species flocks [42]. Daily movement of eastern towhees in loblolly (P. taeda) and longleaf pine (P. palustris) forests and clearcuts in South Carolina averaged 325 feet (99 m) per day. Only 2 females, out of 11 females and 9 males, stayed within the stand where they were captured for the duration of a 10-week study [52].

Eastern towhees have fairly strong fidelity to breeding territories. In an oak forest in New Jersey, adult eastern towhee return rates were 20% the 1st year after banding and 43% in subsequent years. Between 1960 and 1967, the maximum number of eastern towhee returns to the site was 5 [57]. In a Pennsylvania woodlot observed between 1962 and 1967, an eastern towhee returned to the site for 4 consecutive years [79].

Several literature reviews report eastern towhee clutch sizes from 2 to 6 eggs, with means ranging from 2.45 to 3.6 eggs per nest [34,42,67,86]. All 5 eastern towhee nests on Sanibel Island, Florida, contained 3 eggs [74]. Eastern towhees in 2 pitch pine (P. rigida) barrens sites in New Jersey and New York had a later median egg laying date (mid-June) and significantly (p<0.05) smaller average early nest clutch sizes (NJ=2.67, NY=3.25) than those in an oak-hickory (Carya spp.) site, which had a median egg-laying date in early June and an average early nest clutch size of 3.88. Food availability likely explains at least some of the differences between the 2 habitat types [41].

Reviews also note that eggs are incubated by the female for 12 or 13 days. After hatching both parents feed the young, which fledge 10 to 12 days later and are dependent on parental care for about another month [34,42,67,86].

A wide range of eastern towhee nest success values have been reported. On Sanibel Island, 1 of the 5 eastern towhee nests observed was successful. In Louisiana, average daily nest success rate was 95.3% on a bottomland hardwood forest site. The same study found a 92.6% average daily nest success rate in a 6-year-old managed cottonwood (Populus spp.) plantation in Alabama [93]. Average eastern towhee nest success across mixed bigtooth (P. grandidentata) and quaking aspen (P. tremuloides) stands of varying ages in Pennsylvania was 48.1% [103]. In South Carolina, only 1 of 10 nests was successful, and the mean daily nest survival rate was 62.9%. This low value was explained by high levels of predation. Due to lower nest success rates of Bachman's sparrow (Aimophila aestivalis) than the previous year, it is suggested that eastern towhee nest success may have been measured during a comparatively poor year [52].

Compared to nests, adult towhee survival rates are high. Average weekly adult survival rate of eastern towhees in a South Carolina study area was 99.3%. This rate was obtained from radio-marked eastern towhees and represented the pooled survival of both sexes and from 2 South Carolina sites, young and mature stands of loblolly and longleaf pine [52]. Between 1962 and 1967 in Pennsylvania, annual survival of breeding eastern towhees calculated from mistnetting recaptures was 58% [79]. According to a literature review, both males and females become reproductively mature in their 2nd year [42]. Eastern towhees of over 12 years old have been reported in the wild [51].

Eastern towhees spend the majority of their time near the ground. For instance, in Pennsylvania in spring, observations of eastern towhees below 3 feet (1 m) from the ground occurred significantly (p<0.05) more than expected based on random spatial distribution, and observations above 3 feet (1 m) occurred significantly (p<0.05) less than would be expected [102]. In a Louisiana bottomland forest 62% of eastern towhee observations were within 2 feet (0.6 m) of the ground, and only 4% were observed above 25 feet (7.6 m). In the spring this changed, with detections of eastern towhees below 25 feet (7.6 m) declining from 70% to 65% and detections in the canopy (>25 ft (>7.6 m)) increasing from 4% to 7% [24].

Eastern towhees occur in many habitats, from tallgrass prairies [106] and marshes [13] to mature forests [52]. However, eastern towhees are most common in early successional stands, habitat edges (see Effects of spatial arrangement/area), and areas with similar vegetation structure throughout eastern forests.

In most communities eastern towhees are more abundant in young successional stands. Several studies found increased eastern towhee abundance on early successional sites compared to later-successional sites [28,30,49,56,91,102]. Mean number of breeding eastern towhees (0.70 bird/50-m radius) and nest success rate (58%) were higher in a 15-year-old clearcut in west Virginia, than in other treatments, including a stand comprised of yellow-poplar (Liriodendron tulipifera), black cherry, red maple, sugar maple (Acer saccharum), and white ash (Fraxinus americana) that was not harvested [28]. In a southern Missouri oak-hickory forest, eastern towhees were not present before clearcutting or in the nearby uncut forest after cutting, but occurred at a mean density of 9.3 birds/10 ha in a 3-year-old clearcut [91]. A study of stands of varying ages in central New York found that eastern towhee density peaked in early successional stands [49]. The following table shows higher frequencies of eastern towhees in young (≤17 years old) compared to mature (≥40 years old) stands of varying community types in South Carolina [56].

Although eastern towhees generally prefer young successional sites, variation between habitat types and years has been observed. Krementz and Powell [52] found higher relative abundance of eastern towhee in young (2-6 years old) stands of loblolly and longleaf pine than mature (32-98 years old) stands when investigated in 1995. However, in stands compared in 1996, the 95% confidence intervals of eastern towhee relative abundance on the 2 sites had a substantial degree of overlap. The degree to which eastern towhee responds to succession is influenced by habitat. For example, in Pennsylvania there was a significant (p<0.05) difference between eastern towhee densities (number/10 ha) between mature mixed-oak forest and stands that had been clearcut about 5 years previously. However, eastern towhee densities did not differ significantly between a 1-year old mixed aspen (Populus tremuloides, P. grandidentata) clearcut, a 5-year old aspen clearcut, and a mature aspen stand [101]. Eastern towhee abundance has been shown to peak at different times in different habitats. For instance, although in central hardwood forests eastern towhees were most abundant in regenerating stands, in loblolly and shortleaf pine forest they were most common in pole timber and mature stands [25]. In addition, Bell and Whitmore [8] concluded that early successional is likely too broad of a term for describing optimal towhee habitat, since high density of small trees was negatively associated with eastern towhee density in the eastern panhandle of West Virginia.

Eastern towhees seem to prefer sites with characteristics generally associated with early successional vegetation, such as low canopy cover and dense understory. Negative correlations between eastern towhee abundance and various measurements of overstory density have been found in several studies [7,8,20,101]. Average density of eastern towhees across 6 habitat types in Pennsylvania was significantly (p<0.05) negatively correlated with density of overstory trees and basal area of overstory trees [101]. Number of eastern towhees in a western Virginia hardwood forest was also significantly (p<0.05) inversely correlated with total percent canopy cover [20]. In a loblolly pine forest in South Carolina, the average number of eastern towhee breeding territories per experimental unit was significantly (p≤0.008) negatively correlated with mid-story (10-46 feet (3-14 m)) pine (Pinus spp.) and deciduous volume [59].

Many studies have demonstrated a positive correlation between eastern towhee abundance and understory density. In a loblolly pine forest in South Carolina, understory (0-10 ft (0-3 m)) pine volume was significantly (p<0.001) positively correlated with the average number of eastern towhee territories per experimental unit [59]. Yahner [101] found the average density of eastern towhees over 6 habitat types was significantly (p<0.05) positively correlated with density of short (2-5 foot (0.5-1.5 m)) shrubs. In east-central Florida slash pine (P. elliottii) flatwoods with understories dominated by myrtle oak (Q. myrtifolia) and sand live oak (Q. geminata) and in scrub sites with scattered slash pine and cabbage palmetto (Sabal palmetto), eastern towhee densities were significantly (p=0.01) negatively correlated with mean shrub height [14].

Coarse woody debris favors eastern towhee populations. In a loblolly pine forest in South Carolina, experimental removal of downed coarse woody debris resulted in a significant (p=0.042) decline in eastern towhee breeding territories [59]:

Eastern towhees may associate with and avoid certain plants. In riparian vegetation in Iowa, eastern towhee density was significantly (p≤0.01) positively associated with total plant and vine species richness and negatively correlated with forb and deciduous tree species richness [85]. In West Virginia, eastern towhees were associated with plant species that occurred on drier ridgetops, such as blackberry (p<0.02), black cherry (p<0.002), and black locust (p<0.04). These sites tended to have open canopies and low tree density. Eastern towhee density was negatively associated with plants of the moister parts of this study area, such as black tupelo (Nyssa sylvatica, p<0.006), red maple (p<0.001), and witch hazel (p<0.03) [8]. In central New Jersey eastern towhees were significantly (p=0.03) more abundant in gray dogwood (Cornus racemosa) shrubland than either eastern redcedar (Juniperus virginiana) or multiflora rose (Rosa multiflora) shrublands [89].

Nesting habitat: Eastern towhees typically nest on or near the ground. Several literature reviews note the predominance of eastern towhee nests below 5 feet (1.5 m) [34,42,67,86]. In a study of cowbird parasitism on Sanibel Island, all 5 eastern towhee nests located were within 6 feet (2 m) of the ground [74]. Nests as high as 18 feet (5.5 m) have been reported in literature reviews [34,42,67]. Nests higher off the ground in mixed aspen stands of varying ages in Pennsylvania had significantly (p<0.001) lower nest success. Of 13 unsuccessful eastern towhee nests, 11 were greater than 1 foot (0.5 m) above the ground. [103].

Compared to random plots in oak-hickory vegetation in West Virginia (n=421), eastern towhee nesting areas were more likely to contain more grapes (Vitis spp., p=0.0069), fewer small (0-3 inches dbh (0-7.6 cm)) saplings (p<0.001), and fewer large (>15 inches dbh (>38.1 cm)) live trees (p=0.011) [9].

In West Virginia, there were no significant (p>0.05) differences in habitat surrounding successful and unsuccessful nests. Large snags (≥9 inches dbh (≥22.9 cm)) did not have an effect on nesting success [9]. Nesting success was not significantly (p>0.05) affected by stand age or distance to edge in even-aged mixed-aspen stands in Pennsylvania. The table below shows the density of nests and the number of successful nests in stands of varying ages [103].

Eastern towhees nest in a variety of species including grape and blueberry (Vaccinium spp.). The majority of nests observed in South Carolina loblolly and longleaf pine forests and clearcuts were located in grape, tree sparkleberry (V. arboreum), and oak (Quercus spp.) [52]. On an oak-hickory site in West Virginia, 27% of 41 eastern towhee nests were found in grape, 17% in blackberry (Rubus spp.), 12% in greenbrier (Smilax spp.), and 12% in mountain-laurel (Kalmia latifolia). Nests also occurred in Virginia creeper (Parthenocissus quinquefolia), spice bush (Lindera benzoin), and azalea (Rhododendron spp.) [9]. In a power line right-of-way in Pennsylvania, the 6 eastern towhee nests observed occurred in Allegheny blackberry, witch-hazel (Hamamelis virginiana), blueberry (Vaccinium spp.), white oak (Q. alba), eastern hayscented fern (Dennstaedtia punctilobula) and sweetfern (Comptonia peregrina) combined, and on ground level [105]. According to literature reviews eastern towhee nests located on the ground are embedded in litter in dry areas and typically occur at the base of grasses, forbs, low shrubs, or small trees [42,67].

Foraging Habitat: Selection of forging habitat by eastern towhees has been investigated in Massachusetts and New Jersey. When gleaning in a southeastern Massachusetts pitch pine barren, eastern towhees preferred species such as pitch pine, bear oak (Q. ilicifolia), and other deciduous trees, mainly oaks. Ericaceous species were avoided. Use differed significantly (p<0.001) from availability [66]. On 2 New Jersey sites, eastern towhee foraging preference switched over the course of the breeding season [15]. On a site dominated by oaks, primarily black oak (Q. velutina), eastern towhees used oaks in May, as would be expected due to their density. However, in June and July, as relative arthropod biomass declined in oaks, use of oaks was less than would be expected. On a pitch pine-dominated site, use of oaks (primarily bear oak and blackjack oak (Q. marilandica)) was greater than would be expected in May, but was proportionate to availability in June and July. These negative correlations between date and oak use were significant (p<0.025) for both sites. Use of the oak-dominated site also decreased significantly (p<0.05) through the summer. [15].

Effects of spatial arrangement/area: Eastern towhees appear to prefer edge habitats in many areas. For instance, the mean abundance of eastern towhees in a baldcypress (Taxodium distichum)- clearcut edge in northern Florida was 18, while eastern towhees did not occur in either the baldcypress forest or the clearcut. At the interface of the baldcypress stand and a 13-year-old planted slash pine stand, mean abundance of eastern towhees was 22 breeding birds, while in the planted slash pine stand the average abundance was 15 breeding birds [64]. Density of eastern towhees was found to decline with distance from the edge of a power line right-of-way and an oak-hickory forest in eastern Tennessee. At the edge eastern towhees occurred at a density of just over 10 pairs/40 ha, while 197 feet (60 m) from the edge eastern towhee density had dropped to 1 pair/40 ha [53]. In addition, in experimentally clearcut Pennsylvanian forests comprised of white oak, northern red oak (Q. rubra), chestnut oak (Q. prinus), scarlet oak (Q. coccinea), red maple, quaking aspen, bigtooth aspen, and pitch pine [104], male towhees were detected significantly (p<0.05) more often than expected in the areas where the spatial arrangement of clearcuts was most patchy [58].

Several studies have addressed the effect of the size of habitat patches on eastern towhees. In mixed-oak forest in New Jersey, eastern towhee frequency generally increased with patch size, although eastern towhees were detected in all plot sizes (0.5-59 acres (0.2- 24 ha)) except 0.02-acre (0.01 ha) plots [35]. On a site in South Carolina, eastern towhee frequency of occurrence increased as clearcut size increased from <2.5 acres (<1 ha) to clearcut sizes from 21 to about 32 acres (8.5-12.8 ha). On another site eastern towhee frequency declined as clearcut size increased from 19 to 33 acres (7.6-13.2 ha) to 48 to 62 acres (19.5-25.2 ha) [56]. Eastern towhees only bred in riparian vegetation patches in Iowa that were at least 650 feet (200 m) wide [85]. In southern and eastern Pennsylvania eastern towhee nest success was not significantly (p≥0.10) different on sites with gradual edges and those with more distinct edges between "wildlife habitat openings" and oak-hickory forest [26].

FOOD HABITS:
Eastern towhees primarily eat on the ground, although they also glean from vegetation. In a southeastern Massachusetts pitch pine barren, 73.5% of male and 80.4% of female foraging observations were on the ground [66]. When foraging on the ground eastern towhees use a scratching technique where both feet kick back simultaneously [40,86]. In a laboratory study 4 eastern towhees used this method to successfully obtain seed buried almost 1 inch (2.25 cm) deep [98]. When foraging above ground the majority of time is spent gleaning foliage [66]. In Massachusetts, 22.5% of male and 16.3% of female foraging observations were of food being gleaned from foliage. Eastern towhees were also observed gleaning from twigs, branches, and trunks. When gleaning, eastern towhees occurred significantly (p<0.01) more often on the distal half of tree branches compared to using distal and proximal portions equally (see Foraging Habitat). In 0.5% of male and 0.3% of female foraging observations, eastern towhees hovered. Eastern towhees were never observed catching food out of the air [66].

Eastern towhees eat a variety of plant and animal matter. In literature reviews, eastern towhees are reported to eat seeds and fruits, several invertebrates, and occasionally small amphibians, snakes, and lizards [86]. Reviews report eastern towhees foraging at feeders [17,42]. Reviews show that animal matter makes up a larger proportion of the diet in the breeding season [42,63]. In fall and winter, plants make up 79% and 85% of the diet, respectively. This drops to 53% in spring and 43% in summer [63]. Insects such as beetles (Coleoptera), grasshoppers and crickets (Orthoptera), ants, wasps, and bees (Hymenoptera), and moths and caterpillars (Lepidoptera) are common prey items. Eastern towhees eat other invertebrates such as spiders (Araneae), millipedes (Diplopoda), centipedes (Chilopoda), and snails (Gastropoda) to a lesser extent [42,63]. Plants that comprise at least 5% of the eastern towhee diet include ragweed (Ambrosia spp.), oak, smartweed (Polygonum spp.), and corn (Zea mays) in the Northeast and blackberry, oak, panicgrass (Panicum spp.), ragweed, and wax-myrtle (Morella cerifera) in the Southeast [63]. The following table, adapted from Greenlaw's [42] literature review, shows the relative total volume (%) and frequency of occurrence (%, in parentheses) of different food items found in the stomach contents of adult eastern towhees.

Brown-headed cowbirds (Molothrus ater) parasitize eastern towhee nests. In a South Carolina old field 5 of 19 eastern towhee nests were parasitized [100]. Each parasitized nest contained 1 brown-headed cowbird egg. The desertion rate for parasitized nests was 20%, which was similar to nests that had not been parasitized (21%). Two of the five brown-headed cowbird eggs produced fledglings. The study did not determine if there was a difference in nest success between parasitized and nonparasitized nests [100]. In West Virginia, only 3 of 41 eastern towhee nests were parasitized by the brown-headed cowbird. Average number of fledged young in nonparasitized nests was 2.8, which was similar to the average of 2.7 fledglings per parasitized nest [9]. In a Pennsylvania study site, only 2 of 36 nests were parasitized and both produced eastern towhee fledglings [26]. In a study of nest parasitism on Sanibel Island, none of 5 eastern towhee nests found were parasitized [74].

FIRE EFFECTS AND USE

• DIRECT FIRE EFFECTS ON ANIMALS
• HABITAT-RELATED FIRE EFFECTS
• FIRE USE

It is likely that eggs and young birds are much more vulnerable to fire. Although there were no data directly investigating eastern towhee nest mortality due to fire as of early 2006, literature reviews have used life history characteristics to speculate on possible effects of fire on nesting success and bird populations [62,77]. Since eastern towhees nest near the ground, low-severity surface fires during the breeding season could result in considerable nest mortality. However, the degree to which a population would be affected by fire would depend on several factors including occurrence of renesting, season of burn, fire interval, fire uniformity, and fire severity. Since eastern towhees have the tendency to renest, this may mitigate at least some of the impact a breeding-season fire would have [62,77]. Over 2 breeding seasons, 7 of 33 eastern towhee nests observed in a mature loblolly pine forest that had burned between 1 to 2 and 3 to 4 years earlier produced at least 1 fledgling [99]. The daily nest survival rate was 89%, and a mean of 0.68 fledgling was produced per active nest. These values could not be compared to the unburned site due to the lack of nests found there [99]. Higher [93] and lower [52] daily nest survival rates have been reported for eastern towhees in other areas (see Timing of Major Life History Events).

Given that eastern towhees are strongly associated with low woody cover (see Preferred Habitat/Cover), their response is likely influenced by the interaction of habitat type, fire interval, fire uniformity, and fire severity. In habitats such as loblolly-shortleaf pineland and slash pine flatwoods, fairly frequent low-severity fires appear to benefit eastern towhees [14,30,99]. However in habitats such as tallgrass prairie, frequent fires eliminate eastern towhee from the habitat [106], likely due to a decline in shrubby cover. Patchy fires may benefit eastern towhees, due to increased edge (see Effects of spatial arrangement/area) and decreased damage to existing understory vegetation. Due to their cover requirements (see Preferred Habitat/Cover), eastern towhees may be affected by fires severe enough to seriously impact understory vegetation [94]. In cover types where eastern towhees occur primarily in early successional habitat, large stand-replacing fires may create patches that would provide eastern towhee habitat several years after the burn. Eastern towhees have been observed on a sand pine (Pinus clausa) scrub site in Florida 3 to 7 years after it was burned in a severe wildfire and subsequently salvage logged [38].

Eastern towhee's response to fire depends in part on the vegetation community. In some habitat types eastern towhees are present soon after burning, while in other habitat types eastern towhees do not occur on recently burned areas. For example, the average number of eastern towhee detections per census was approximately 5 on an old field pineland in Florida that had been winter-burned annually for approximately 30 years [30]. In Arkansas, eastern towhees occurred at a density of 6 territorial males/40 ha the spring following a winter burn in a field that had been dominated by broomsedge bluestem (Andropogon virginicus) and sassafras (Sassafras albidum) saplings [81]. Eastern towhees were also observed on wetlands burned 6 months earlier [95]. However, in an Indiana oak forest that had been surface burned 1 to 2 years and 3 to 4 years before sampling, eastern towhees were absent despite their occurrence in unburned control plots [5]. Eastern towhees did not occur in annually burned tallgrass prairies, but were observed in unburned (>10 years) tallgrass prairie in some years [106]. Eastern towhees did not occur in frequently burned longleaf pine sandhill plots [75]. In areas of Minnesota where frequent (12-26 fires in 32 years) fires were being used to restore oak savanna once dominated by bur oak (Quercus macrocarpa) and northern pin oak (Q. ellipsoidalis), eastern towhees were associated with unburned vegetation [21].

In some habitats eastern towhees increase after prescribed surface fires. Shortly after fire was excluded from an old-field loblolly-shortleaf (P. echinata) pineland that had previously been burned annually, eastern towhee occurrence increased. Eastern towhee detections per census increased from approximately 5 in postfire year 1 to over 12 in the 4th postfire year. After 4 years eastern towhee detections gradually declined. After 11 years of fire exclusion, eastern towhee detections were less than in the 1st postfire year. Due to eastern towhee absence in a beech-magnolia (Fagus-Magnolia spp.) stand, the authors predicted that as succession continues and the proportion of deciduous canopy increases, eastern towhees will eventually leave the site [30]. In coastal scrub and slash pine flatwoods in east-central Florida, eastern towhee densities were significantly (p=0.007) higher (4.5/ha) on sites that had burned 4 years before the survey than those that had been burned 1 year before (2.3/ha), 2 years before (3.3/ha), or more than 10 years before (2.6/ha) the survey [14]. The habitat with the greatest number of eastern towhees detected on Eglin Air Force Base in Florida was a "mature flatwoods" that had been burned 1 to 5 years before the survey. Eastern towhee detections in this habitat were significantly (p<0.05) greater than in both the burned (1-3 years previously) and unburned (for several decades) sandhills dominated by mature (>50 yr) longleaf pine [92]. In a loblolly pine forest with a mid-story dominated by oaks (Quercus spp.) and hickories (Carya spp.), eastern towhee abundance was significantly (p<0.05) greater on sites that had been burned either 1 year, 2 years, or 3 years before sampling (detections/count/site=3.79) compared to sites that had not been burned for more than 20 years (detections/count/site=1.44). Eastern towhees were also observed at higher frequencies in burned areas (89%) compared to unburned areas (74%) [99]. Three areas in Pennsylvania, one unburned area, one that had been burned 1 year earlier, and one that had been burned 2 years earlier were comprised of various habitats including a bluestem (Andropogon spp.) community, a scrub oak (bear oak and dwarf oak (Q. prinoides) community, a scrub oak-mixed aspen community, a scrub oak-pitch pine community, and a scrub oak-mixed-oak community. Eastern towhees were the most common bird in all three areas, but occurred at the highest density, approximately 0.67 singing male/ha, in the 2-year-old burn. In the unburned it occurred at a density of about 0.43 singing male/ha, and in the 1-year-old burn singing male eastern towhees occurred at a density of about 0.38/ha [83].

Differences in vegetation structure after burning may explain at least some of the variation in eastern towhee's response. A literature review demonstrated that changes in bird communities after fire are associated with the degree of structural change in the vegetation. More structurally complex habitats and more severe fires result in longer periods before the prefire bird community returns. For instance, the prefire bird community is typically restored about 3 years after a grassland fire, while it can take over 30 years for the prefire bird community to return after a stand-replacing forest fire [48]. Data on vegetation in areas where eastern towhee did and did not occur after fire show the effects of much smaller changes in vegetation structure. Vegetation on burned and unburned areas differed in an investigation that found significantly (p<0.05) higher eastern towhee abundance in burned areas. The unburned stands of loblolly pine with an understory of oaks and hickories had significantly (p<0.05) more hardwoods and total trees (≥7.5 cm dbh/ha), more snags and logs (≥7.5 cm/ha), higher percentage canopy closure, higher percentage of leaf litter, and lower percentage of herb cover than burned plots [99]. In contrast, an Indiana study area comprised of oak (Quercus spp.) dominated forests, chestnut oak (Q. prinus) woodlands, oak-hickory forests, and American beech (Fagus grandifolia)-sugar maple forests that were burned twice in 4 years had lower density of small 1 inch (<2.5 cm) dbh live woody stems and less horizontal vegetation cover below 1.6 feet (0.5 m) than the unburned site. In this study, eastern towhees were observed in the unburned vegetation, but not in the burned area [4,5].

Severity of the fire is also likely have a major impact on eastern towhee's response. In a literature review, it is suggested that fires of any severity are likely to affect ground-nesting birds, since even low-severity fire is likely to have large impacts on the vegetation they use [61]. Rotenberry and others [78] hypothesize in a literature review that "cool" and "intermediate" burns could increase food availability and leave adequate vegetation for ground-nesting birds. Data comparing eastern towhee densities among burns of varying severity are lacking. Observations of a pitch pine barren site in New Jersey shortly after a fairly extensive wildfire occurred in late winter/early spring did provide some information. The number of eastern towhees declined in some burned areas and increased in areas adjacent to the burn area. However, in areas within the burn where the vegetation was only slightly damaged and new growth provided cover, eastern towhee abundance was not affected [94]. In South Carolina, average weekly adult eastern towhee survival rates were not significantly (p=0.15) different in young (2-5 years old) longleaf pine stands than in mature (32-97 years old) longleaf pine stands that were occasionally thinned and surface burned under prescription every 3 to 5 years [52]. Eastern towhees were observed on a sand pine scrub site in Florida subject to a stand-replacing fire and salvage logging between 5 and 7 years before sampling. The following table shows the average density (number/km²) of eastern towhees on the burned and salvaged site and on a mature (≥55 years since stand-replacing fire) forest site [38].

Seasonal effect of burning on eastern towhee is uncertain. Literature reviews suggest that burns during the breeding season are likely to have a larger impact on ground-nesting birds, both directly through nest mortality and indirectly through greater and/or more persistent loss of cover than would likely occur from dormant season burns [61,77]. In addition, once territories are established eastern towhees may be less likely to leave a burned area [29]. No studies to date (2006) have compared eastern towhee demographics on sites burned in varying seasons. However, comparisons of eastern towhee abundance on sites burned during dormant and growing seasons have not resulted in detectable effects. On sites burned every 2 to 4 years in pure and mixed stands of longleaf, loblolly, and shortleaf pine in Georgia, eastern towhee abundance on sites burned between April and August (average of 1.54 birds/plot) was not significantly (p=0.32) different from the sites burned between January and March (average of 2.31 birds/plot) [50]. The following table shows the frequency (%) and abundance (total/40-m radius) of eastern towhees on control plots, plots burned in January, and plots burned in June in a dry prairie/shrubland in southwestern Florida [33]:

Fire is likely to have an affect on the availability of eastern towhee food items. Several literature reviews summarize information regarding changes in plant and animal food availability after fire [23,60,78]. Several shrubby species may increase fruit production after fire, although the response is dependent on the species and postfire environmental factors [23]. Seed and fruit production typically increase after fire in southern forests, with peak production from 2 to 6 years after fire. The frequency and season of burning influence plant recovery and fruit production [60]. Lyon and others' [60] review discusses the effect of fire on invertebrates, some of which are eastern towhee prey. Many of the studies found an increase in arthropod availability after understory fires in southern sandhill and loblolly-shortleaf pine forests [60].

Fire ecology: Eastern towhees occur in a variety of habitats with a wide range of fire regimes. However, areas with the highest towhee densities typically undergo low-severity surface fires at an interval of about 4 to 10 years [14,30]. Fires in the southeastern United States frequently occur in summer due to an increase in the occurrence of lightning strikes [73].

Due to their preference for early successional stands (see Preferred Habitat/Cover), eastern towhees are likely to occur in early to intermediate successional stages after stand-replacing fires.

In herbaceous habitats eastern towhees are most likely to occur in areas where fire exclusion [106] has resulted in establishment of some woody shrubs.

Fire regimes: The following table provides fire return intervals for plant communities and ecosystems where eastern towhee is likely to occur. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes".

Less is known about eastern towhees response to severe fires. In dense-canopied forests, stand-replacing fires may provide patches of early successional vegetation necessary for eastern towhee occurrence. Although there are no data on eastern towhee occurrence in severely burned forest, eastern towhees have increased on sites subjected to other canopy-opening disturbances that may have less effect on the understory, such as wind throw or logging [28,39,91]. On a sand pine scrub site in Florida that was burned in a stand-replacing fire and salvage logged 5 to 7 years earlier, eastern towhees were more abundant than on a mature, control site. The extent to which eastern towhees were responding to the effects salvage logging is unknown [38].

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