Sphyrapicus Varius Research Articles

Influence of surrounding vegetation on woodpecker nest tree selection in oak forests of the Upper Midwest, USA

This study examined the influence of forest context on woodpecker nest tree selection, which has implications for forest managers leaving trees during timber harvest for cavity nesting birds. We surveyed habitat variables in 11.3 m radius subplots centered on 165 active woodpecker nest trees and 144 randomly selected points in oak forests of southeastern Minnesota and western Wisconsin in 1997–1998. Forward stepwise sequential F-tests indicated that the number of potential nest trees and basal area (BA) of dead elms were the most important variables in distinguishing nest sites and random sites. Discriminant function analysis correctly classified 71% of the observations. However, a comparison of nest sites only to those random sites containing a tree likely suitable for nesting showed no differences. This suggests that nest tree has a greater influence in nest site selection than does surrounding vegetation. Yellow-bellied sapsucker nest trees were surrounded by a significantly higher BA of trembling aspen ( Populus tremuloides) and density of mast-producing trees than the nest trees of the downy, hairy, red-bellied, red-headed, and pileated woodpeckers, and the northern flicker. However, we found no interspecific differences among downy, hairy, red-bellied, and red-headed woodpeckers. This study is significant because it indicates forest management for cavity nesting birds should focus on providing suitable nest trees within the larger forest context; vegetation immediately surrounding nest trees may have minimal influence on woodpecker nest tree selection.

Low Frequency of Site Fidelity by Golden-Fronted Woodpeckers

Interest in site fidelity is rooted in its influence on population structure, including dispersal and recruitment (Shields, 1984). Familiarity with the local habitat is increased through fidelity, which in turn may enhance defendability and access to the best nesting, staging, and wintering sites. Factors proposed that might influence the degree of site tenacity include age, sex, local habitat and nest-site stability, and prior breeding experience (Shields, 1984). Ideally, statistical analysis of site fidelity should include data on mortality-survival rates and dispersal distance. For the golden-fronted woodpecker (Melanerpes aurifrons) these data are unavailable (Husak and Maxwell, 1998) so we discuss site faithfulness in this species relative to that documented for congeners. Fidelity has been documented among migratory and non-migratory birds (e.g., Freer, 1979; Greenwood, 1980; Shields, 1984; Blancher and Robertson, 1985; Rimmer and Darmstadt, 1996; Flint et al., 2000; Weggler, 2000), but few studies have focused on woodpeckers. In North America, nest-site fidelity has been documented in red-cockaded (Picoides borealis; Jackson, 1994), red-headed (Melanerpes erythrocephalus), and red-bellied (M. carolinus) woodpeckers (Ingold, 1991), and migratory northern flickers (Colaptes auratus), and yellow-bellied sapsuckers (Sphyrapicus varius; Lawrence, 1967). The only site fidelity data for golden-fronted woodpeckers prior to our research involved anecdotal observations of re-use of nest sites over

Use and Selection of Sap Trees by Yellow-Bellied Sapsuckers

AbstractYellow-bellied Sapsuckers (Sphyrapicus varius) obtain phloem sap from clusters of holes that they peck in living trees. I examined trees that sapsuckers used for sap extraction in northern Michigan and tested several hypotheses to explain why they choose specific trees for attack and why they cluster their holes in one place on the bole of each of these focal trees. Sapsuckers preferentially attacked individuals of paper birch (Betula papyrifera), red maple (Acer rubrum), juneberry (Amelanchier sp.) and bigtooth aspen (Populus grandidentata). They made clusters of sap holes an average of 7.13 m from the ground and within 1 m of a live branch; most clusters were located above old holes or other wounds from previous years. Each new sap incision through the bark to the phloem stream was made above a previous one and was enlarged for an average of 3.1 days before being abandoned for a new, higher hole. The resulting long vertical chains of holes were made alongside others to form tight clusters of holes at a single spot on the tree. Sapsuckers did not select trees for sap extraction based on location relative to nesting sites or on microclimate conditions of water availability and tree density. Individual trees used for sap extraction did not have thinner bark, more moisture in bark samples, or larger crowns, but they did score lower in an index of overall tree health. Experimental evidence suggested that sapsuckers cluster their holes to induce the accumulation of sap in bark that they will attack for future sap extraction. Thus, sapsuckers appear to overcome some of the difficulties in obtaining phloem sap by choosing specific species and individuals, clustering sap holes above previous wounds, and possibly by farming their resource throughout the season by girdling the tree's phloem stream with each successive sap incision. I attempted to duplicate the wounding techniques and patterns of wounding of sapsuckers but was unable to induce sap flow from the same or similar trees in the area.

USE AND SELECTION OF SAP TREES BY YELLOW-BELLIED SAPSUCKERS

Abstract Yellow-bellied Sapsuckers (Sphyrapicus varius) obtain phloem sap from clusters of holes that they peck in living trees. I examined trees that sapsuckers used for sap extraction in northern Michigan and tested several hypotheses to explain why they choose specific trees for attack and why they cluster their holes in one place on the bole of each of these focal trees. Sapsuckers preferentially attacked individuals of paper birch (Betula papyrifera), red maple (Acer rubrum), juneberry (Amelanchier sp.) and bigtooth aspen (Populus grandidentata). They made clusters of sap holes an average of 7.13 m from the ground and within 1 m of a live branch; most clusters were located above old holes or other wounds from previous years. Each new sap incision through the bark to the phloem stream was made above a previous one and was enlarged for an average of 3.1 days before being abandoned for a new, higher hole. The resulting long vertical chains of holes were made alongside others to form tight clusters of ho...

Secondary Use of Aspen Cavities by Tree-Roosting Big Brown Bats

To further explore natural roost-site selection by temperate bats, we examined the use of tree roost sites by big brown bats ( Eptesicus fuscus ) in the West Block of Cypress Hills Provincial Park, Saskatchewan, an area where the number of human structures is limited. In this area, we found big brown bats roosted exclusively in cavities of trembling aspen trees ( Populus tremuloides ), despite the availability of cavities in snags of conifer trees. Most cavities had been excavated and previously used by yellow-bellied sapsuckers ( Sphyrapicus varius ). The use of aspens by sapsuckers relates to the relatively soft wood and susceptibility to heart rot of these trees, which provide ideal conditions for nesting: decayed heartwood with a firm sapwood shell. Orientation of cavity entrances was close to due south. The width of bats and the width of cavity entrances differed, suggesting that bats are not using roosts for protection from predators or exclusion of competitors. Bats showed fidelity to a particular group of roost trees because, despite roost switching, bats reunited in subsequent roost sites. During the day, temperatures in aspen cavities were approximately 50C cooler than in cavities of conifer snags. Microclimate differences, including temperature, may be why aspen cavities are selected over available cavities in conifer snags. All of the randomly selected cavities in aspen that we searched showed evidence of use by bats, which suggests roost sites for big brown bats in southwestern Saskatchewan may be a limiting resource.

A Test of an Environmental Advertisement Hypothesis for the Function of Drumming in Yellow-Bellied Sapsuckers

The woodpecker drum is unusual among avian acoustic display because woodpeckers employ material outside their own bodies to produce sound. This allows an opportunity for acoustic analysis of instruments used for drumming that is not possible with other types of acoustic display. Examination of the drum sites of Yellow-bellied Sapsuckers (Sphyrapicus varius) revealed that sapsuckers do not use drumming to advertise the presence of nesting and feeding sites in their environment. Controlled hits on a variety of substrates in the sapsuckers' environment were used to compare acoustic properties of spots chosen for drumming to other non-drum spots. In general, sapsuckers drummed in locations that could produce louder and longer lasting sounds than surrounding non-drum substrate including nest trees, feeding trees, and other substrate near the site of drumming. My evidence suggests that sapsucker drumming is an acoustic signal designed for long distance transmission.

Nest tree use by primary cavity-nesting birds in south central British Columbia

Heartwood decay was the most important factor in nest tree selection by primary cavity-nesting birds in the Interior Douglas-fir Biogeoclimatic Zone of British Columbia. Of 243 active nests, most were in trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera). Douglas-fir (Pseudotsuga menziesii) and hybrid spruce (Picea engelmannii × glauca) were not used for nesting. Strong excavators (Yellow-bellied Sapsucker (Sphyrapicus varius), Pileated Woodpecker (Dryocopus pileatus), and Hairy Woodpecker (Picoides villosus)) preferred to nest in live trembling aspen with heartwood decay. Weak excavators (Red-breasted Nuthatch (Sitta canadensis), Northern Flicker (Colaptes auratus), and Downy Woodpecker (Picoides pubescens)) preferred to nest in dead trees or dead tops of live trees. Yellow-bellied Sapsucker preferred to nest in trees larger than 30 cm diameter at breast height, and Pileated Woodpecker preferred trees larger than 40 cm diameter at breast height. No significant preference for nest tree diameter was detected for other species.

Characteristics of Northern Hardwood Trees Used by Cavity-Nesting Birds

Characteristics of Northern Hardwood Trees Used by Cavity-Nesting Birds

Speciation in Sapsuckers (Sphyrapicus): I. Genetic Differentiation

Abstract We report the results of an electrophoretic analysis at 39 presumptive genetic loci of 88 specimens in the picid genus Sphyrapicus, here treated as comprising the following species: Williamson's Sapsucker (S. thyroideus), Yellow-bellied Sapsucker (S. varius), Red-naped Sapsucker (S. nuchalis), and Red-breasted Sapsucker (S. ruber). Seventeen loci (43.5%) were polymorphic. Values for observed heterozygosity in S. ruber ruber, S. ruber daggetti, and in three populations of S. nuchalis were uniform and averaged 0.043, the mean value reported for other birds. However, S. varius, at 0.022, and S. thyroideus, at 0.016, have low values of H. Values for percentage of polymorphic loci ranged from 12.8 to 20.5 in S. ruber and S. nuchalis, 12.8 in S. varius, and 7.7 in S. thyroideus. In contrast, all four species exhibited a similar mean number of alleles per locus (1.12-1.21). Genetic distances between populations of the same species are either very low or zero. Genetic distances are also very low between the phenotypically dissimilar ruber and nuchalis (D̄ = 0.004), two forms we consider to be biological species based on their assortative mating in sympatry. This is the lowest avian interspecific D-value ever reported and is similar to that found between avian subspecies. Phenotypically, varius and nuchalis are very similar, yet the average genetic distance between samples of these forms, 0.029, is comparable to interspecific values reported for other avian congeners and is our chief basis for treating the two forms as separate species. S. thyroideus is strongly differentiated genetically from varius (D̄ = 0.142), from nuchalis (D̄ = 0.197), and from ruber (D̄ = 0.186). FST statistics point to little or no population subdivision within ruber and nuchalis but substantial subdivision within the superspecies varius (S. varius + S. nuchalis + S. ruber). The genetic information suggests that the Williamson's Sapsucker represents the oldest lineage in the genus. S. thyroideus split from its sister clade (superspecies S. varius) between 3 and 4 MYBP. S. ruber and S. nuchalis are sister species that evolved very recently, either during or since the Pleistocene and sometime after their common ancestor diverged from S. varius.

Hummingbird–sapsucker associations in northern climates

The ruby-throated hummingbird has the most extensive breeding distribution of any hummingbird species in North America. In its most northern distribution in Canada, its spring arrival often occurs before herbaceous flowers are in bloom, and in many parts of its range it breeds in habitats where floral nectar is scarce or unavailable. Evidence is presented to support the hypothesis that the dates of spring arrival and northern breeding distribution of the ruby throat, and probably the rufous hummingbird, are determined by a commensal relationship with the yellow-bellied sapsucker, in which the principal energy source for the hummingbirds is sucrose in sap from trees drilled by the sapsuckers.

A comparison of foliage use and tree height selection by birds in unlogged and logged mixed-coniferous forest

Tree height selection and use of the available foliage by birds were examined in two mixed-coniferous forests in the White Mountains, Arizona, USA, during 1973 and 1974. A comparison of avian habitat use between a natural forest and one which had recently undergone a moderately heavy overstory removal form of timber harvesting, revealed that in both areas tall and moderately tall trees were preferred. Comparisons were made for the composite avian community and, in particular, for the yellow-bellied sapsucker Sphyrapicus varius, mountain chickadee Parus gambeli, ruby-crowned kinglet Regulus calendula, yellow-rumped warbler Dendroica coronata, and dark-eyed (= grey-headed) junco Junco hyemalis caniceps. Taller trees provided substantially more foliage and substrate for nesting and foraging than did shorter ones. Foliage use by birds in the unharvested plot suggested that foliage was being used in approximately the proportion in which it was available. This was not true in the modified plot where quaking aspen Populus tremuloides—the only tree species not logged—comprised 53·1% of the total available foliage volume. The biggest discrepancy between bird use and foliage volume occurred between 9 and 21 m from the ground. Within this height interval aspen represented 63·8% of the total volume. The subsequently derived bird use curve reflected the reduced desirability of aspen for most avian species.

On Habitat Selection of Williamson's and "Red-Naped" Yellow-Bellied Sapsuckers

On Habitat Selection of Williamson's and "Red-Naped" Yellow-Bellied Sapsuckers

Energetics of Feeding on Tree Sap by Ruby-Throated Hummingbirds in Michigan

Nest location and feeding energetics of ruby-throated hummingbirds (Archilocus colubris) were examined in northern Michigan. The hummingbirds fed on tree phloem sap made available by holes drilled by yellow-bellied sapsuckers (Sphyrapicus varius). During the nesting season females were specialists, feeding almost exclusively on tree sap and rarely taking flower nectar. All six nests studied were within 300 m of a sapsucker feeding tree. Laboratory studies indicated that the birds could be fully supported by the feeding trees, which contained phloem sap at a concentration of 16 g sugar per 100 g solution (0.47 M sucrose equivalent). In northern Michigan, rubythroated hummingbirds were energetically coupled to the feeding trees of sapsuckers and thus achieved reduced energy costs in this northern climate.

Sapsucker Hybridization in British Columbia: Changes in 25 Years

Howell (1952) reported interbreeding between two races of the Yellow-bellied Sapsucker, Sphyrapicus varius and S. v. nuchalis, in the Cariboo area of south-central British Columbia, Canada. The American Ornithologists' Union Check-list (1957, 1973) treated these populations as conspecific, but Mayr and Short (1970) considered them as distinct species, S. and S. nuchalis. In particular, Howell (1952) noted that the former replaced the latter within a distance of less than 8 km, centered approximately on the village of Kersley (see maps in Howell 1952: 260, 266). While working in British Columbia in 1973, Ankney collected eight sapsuckers in the area studied by Howell. He collected three at McLeese Lake, about 50 km by air S of Kersley. He found none at Kersley but collected five at Bouchie Lake, about 25 km by air NNW of Kersley. Two of these were nuchalislike. In 1950, all those found north of Kersley were typical ruber (Howell 1952:265). Thus, the sample from Bouchie Lake suggested that the zone of contact had extended northward since 1950. Because information on spatial changes in overlap and hybrid zones is not abundant (Selander 1971), we attempted in 1974 to confirm the inferred change in the contact zone between and nuchalis.

Nest Site Selection by Williamson and Red-Naped Sapsuckers

Two congeneric woodpeckers, the Williamson Sapsucker (Sphyrapicus thyroideus) and the Red-naped Sapsucker (S. [varius] nuchalis) are sympatric throughout much of the Rocky Mountain region of the western United States. Although these two picids are closely enough related that two probable hybrids have been reported (Short and Morony 1970), there is generally effective reproductive isolation between them. This reproductive isolation apparently is not due to different nest site preferences. Bent (1939), Packard (1945), Bailey and Niedrach (1965), and Burleigh (1972) reported that Red-naped Sapsuckers prefer deciduous trees, especially aspen (Populus tremuloides), while Williamson Sapsuckers favor conifers. However, Rasmussen (1941), Hubbard (1965), and Tatschl (1967) noted that thyroideus nest in aspen, which Ligon (1961) suggested was their preferred nest tree in northern New Mexico. These differences in the literature led us to investigate the nesting habitat preferences of the two sapsuckers in Colorado and Wyoming. We use the name Rednaped for the Rocky Mountain form of the Yellowbellied Sapsucker (S. varius) complex, as suggested by Short (1969) and Short and Morony (1970). We examined a total of 57 thyroideus and 46 nuchalis nests at two locations in Colorado and one location in Wyoming. Both species nested at each location and were provided a choice of nest trees by the close proximity of conifers and aspen (fig. 1 and 2). At each nest site, we recorded the species and condition of the nest tree, its diameter at breast height (dbh, measured at 4.5 feet above the ground), the height of the nest hole, and the compass direction that the hole faced. We also measured various nest stand parameters, including stand density and stand size. These data were examined for significance using t-test and Chi-square statistical analyses. The primary study area, in northern Colorado, consisted of six sites within the eastern half of Rocky Mountain National Park, Larimer County. Elevations at which nests were found ranged from 2440 to 2800 m, roughly corresponding to the upper montane region and the upper montane/subalpine ecotone region of Marr (1967). The area was predominantly an open forest of ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii), with lodgepole pine (P. contorta) on cooler north-facing slopes and with limber pine (P. flexilis) in exposed areas above 2700 m. Aspen occurred in discrete stands along permanent to ephemeral drainages within the coniferous forest (fig. 1). The understory was highly variable due to topographic differences but was always rather sparse and low. The second Colorado study area was located on Missionary Ridge, about 20 mi NE of Durango, La Plata County. Elevations here ranged from 2500 m at Wallace Lake to 2900 m atop surrounding hillsides. Mature aspen ringed the ephemeral lake and extended up the adjacent slopes along drainages (fig. 2). Drier areas were covered by a coniferous forest of ponderosa pine, Douglas-fir, white fir (Abies concolor), and blue spruce (Picea pungens). Open areas on hillsides were covered by a dense growth of scrub oak (Quercus gambelii) and snowberry (Symphoricarpos oreophilus). Grasses, sedges, and forbs grew in a lush understory beneath the aspen, with kinnikinnik (Arctostaphylos uva-ursi) under the denser spruce/fir forest. Ground cover was sparse under the Douglas-fir/pine forest. The third study area was located in the Bridger Wilderness on the west slope of the Wind River Mountains, 40 mi NE of Pinedale, Sublette County, Wyoming. Nests were found from 2440 to 3200 m. Areas at lower elevations were covered by a forest of aspen interspersed with Englemann spruce (P. englemannii), Douglas-fir, and lodgepole pine. Areas at higher elevations had a forest of mixed spruce and subalpine fir (A. lasiocarpa) with patches of lodgepole pine and small stands of aspen, the latter occurring as late seral stages and being replaced by spruce and fir. At all three study locations, the two sapsucker species showed a strong preference for aspen (table 1), in which 85 percent of thyroideus nests and 100 percent of nuchalis nests were located. The close proximity of aspen and conifers at the three sites

Habitat Utilization by Four Species of Woodpeckers in a Central Illinois Woodland

A sympatric guild consisting of the red-headed woodpecker (Melanerpes erythrocephalus), the downy woodpecker) (Dendrocopus pubescens), the red-bellied woodpecker (Centurus carolinus) and the yellow-bellied sapsucker (Sphyrapicus varius) segregated realized niches by: (1) differential foraging techniques; (2) exploiting different height classes; (3) selection of different tree species; (4) use of relative different amounts of alive and dead substrate; (5) differential selection of limb size. In downy woodpeckers, sexes separated the species' realized niche into subniches, which in the past may have caused evolution of different bill structures. Yellow-bellied sapsuckers exploited primarily a sap resource from hickory trees while in wigration. They foraged on larger limbs at lower levels. Red-headed woodpeckers had a more restricted woodland foraging pattern than did downies and red-bellied woodpeckers. Red-heads, however, spent more time out of the wooded area. Intersexual overlap values for the sexually dimorphic downies were greater than interspecific values. INTRODUCTION The principle of competitive exclusion (Hardin, 1960) implies that ecologically sirnilar, cohabiting species should exhibit various degrees of evolutionary divergence which reduce competition and thus increase fitness. The nature of divergence or niche differentiation of sympatric species of birds has been the subject of several ecological investigations, and differential foraging patterns have been found to be a major factor permitting coexistence (Dixson, 1961; Koplin, 1969; Lack, 1954; MacArthur, 1958; Root, 1966; Willson, 1970). Evolutionary divergence also occurs intersexually, presumably to reduce competition and thus allow strengthening of the pair bond. Davis (1965) and Selander and Giller (1959) have shown that sexual dimorphism in bill length exceeds that in other size characters in most species of woodpeckers. Selander (1966) discussed the role of bill dimorphism in reducing intraspecific competition and presented evidence that in Centurus striatus on Hispaniola, both bill sizes and feeding behavior of the sexes were different. Red-headed woodpeckers (Melanerpes erythrocephalus), downy woodpeckers (Dendrocopus pubescens), red-bellied woodpeckers (Centurus carolinus) and yellow-bellied sapsuckers (Sphyrapicus varius), all occur in central Illinois during the early spring. This study was initiated to quantify the behavioral and habitat use patterns which segregate these species and any intersexual differences in behavioral and habitat use patterns in the downy woodpecker. Specific questions to be answered were: (1) how does a sympatric guild of woodpeckers segregate its respective niches; (2) are the real-

Recent Bird Records from the Guadalupe Mountains, Texas

New, or verification of old, records for seventeen species of birds occurring in the southern Guadalupe Mountains, Culberson Co., Texas, are reported. Specimens of Caprimulgus vociferus, Eugenes fulgens, Sayornis nigricans, Nucifraga columbiana, Catharus ustulatus, Vireo olivaceus, Dendroica pensylvanica, and Icterus cucullatus, were collected and represent the first specimen records of these species for the Guadalupe Mountain region of Culberson Co. Sightings and specimen records indicate that Buteo albonotatus, Falco peregrinus, Actitis macularia, Eugenes fulgens, Sphyrapicus varius, Empidonax oberholseri, Vermivora virginiae, Icterus cucullatus, and Loxia curvirostra breed, or are potential breeders, in the area under consideration. The southern Guadalupe Mountains, part of Guadalupe Mountains National Park, are located in Trans-Pecos Texas approximately 100 mi E of El Paso and about 40 mi SW of Carlsbad, New Mexico (Fig. 1). The New Mexico state line forms the northern boundary of the national park. A part of this northern boundary is contiguous with Lincoln National Forest. The better known (biologically) Davis and Chisos Mountains are located 100 and 200 miles, respectively, to the southeast of the Guadalupe Mountains. The first recorded work on birds in the southern Guadalupe Mountains was that of Vernon Bailey in 1901 (Bailey, 1905). In 1938 and 1939 Thomas D. Burleigh and George H. Lowery, Jr., collected specimens in the Guadalupe Mountains (Burleigh and Lowery, 1940). W. B. Davis, along with several students, also recorded Guadalupe bird life during the late 1930's and early 1940's (Biaggi, 1942). The vegetation of the Guadalupe Escarpment was analyzed by F. R. Gehlbach (1967). Fred and Nancy Gehlbach surveyed breeding birds in the Guadalupes during their field investigations in the late 1950's and 1960's. 1 Present address, Dept. of Biology, Hardin-Simmons University, Abilene, Texas 79601.

Methods and Annual Sequence of Foraging by the Sapsucker

No fewer than 13 species of woodpeckers have been recorded feeding at the phloem sap of trees as it flows from wounds, and at least 7 of them are known to produce the wounds in the phloem that let the sap flow: Members of the nearctic genus Sphyrapicus differ markedly from other woodpeckers by their modifications for sap feeding. The role this plays in the daily activities of the Yellow-bellied Sapsucker (Sphyrapicus varius) has not been emphasized. The biology of the Yellow-bellied Sapsucker is best known from studies of S. v. varius, which breeds throughout the coniferous-deciduous ecotone of northeastern United States and Canada east of the Rocky Mountains. Some basic life history information was gathered by Baird (Baird et al. 1874), Bendire (1888), and Forbush (1921). Howell's (1952) lucid discussion of differentiation in four races of the Yellowbellied Sapsucker includes some natural history and comparative behavioral information. Kilham (1962) presented a sketchy account of the breeding biology of the northeastern race. The most complete account of the breeding behavior of S. v. varius was done by Lawrence (1967). In this paper the term sapsucker means S. v. varius unless otherwise stated. A controversy over the major food source of the sapsucker arose in the early 1900s. The species was condemned as injurious to trees, and its sap-drilling habits were attributed to the production of an attractive concentration site for edible insects (see Townsend 1932). Reports on various forms of damage caused by Yellow-bellied Sapsuckers continue to appear (Shigo 1963, Ohman and Kessler 1964, Shigo and Kilham 1968). Bolles (1891) was one of the first to discuss the attraction that phloem sap has for other organisms at the sapsucker tree. Many authors, including McGuire (1932), Batts (1953), Kilham (1953a, 1953b, 1958, 1964), and Nickell (1956, 1965), have added to the list of animals seen at sapsucker trees. The interactions of other organisms using sapsucker trees were analyzed by Foster and Tate (1966). McAtee (1911) summarized the early literature listing the species of plants sapsuckers feed upon.

Bendire's Records of Red-Shouldered Hawk (Buteo lineatus) and Yellow-Bellied Sapsucker (Sphyrapicus varius nuchalis) in Oregon

Bendire's Records of Red-Shouldered Hawk (Buteo lineatus) and Yellow-Bellied Sapsucker (Sphyrapicus varius nuchalis) in Oregon

A note on the sporogony of Parahaemoproteus velans (=Haemoproteus velans Coatney and Roudabush) (Haemosporidia: Haemoproteidae) in species of Culicoides.

Sporogony of Parahaemoproteus velans (= Haemoproteus velans Coatney and Roudabush) was followed in two Culicoides spp. at intervals after feeding on yellow-bellied sapsuckers (Sphyrapicus varius) harboring gametocytes. Cyclical development of the parasite was completed within 96 h at 20 °C. Mature oocysts were small and contained fewer than 50 sporozoites that arose from a single germinal mass. Sporozoites were infective to two uninfected yellow-bellied sapsuckers.