Birds and Birding
Avian Surveys of Macphail Woodlot

red-breasted nuthatch.

Avian Surveys of the Sir Andrew Macphail Woodlot at Orwell, Prince Edward Island 1993 to 1995. by Scott Makepeace

• Introduction
• Methods
• General
• Structured Bird Surveys
• Results and Discussion
• General
• Bird Identification Tours
• Structured Surveys
• General
• Bird Community Composition
• Abundance
• Individual Points
• Casual Observations
• Summary
• Literature Cited

This paper is a detailed look at the observations of avian breeding activites at the Macphail Woodlot. It covers a period of three years, 1993 through to 1995.

There are plans in the works to renew this monitoring activity for the 1998 field season.

List of Tables
Table 1. Bird species and abundance indices as determined by structured bird surveys and casual observations made in the Macphail Woodlot, June 4th to July 17th, 1995.

Table 2. Mean abundance (over all points) and 95% Confidence Interval (CI) for selected bird species in the Macphail woodlot, 1993 to 1995, P.E.I.

Table 3. Total bird species richness, mean species richness and bird community diversity for six survey points surveyed in 1993 to 1995 at the Macphail woodlot

Table 4. Abundance indices for three bird species over six survey points for 1993, 1994 and 1995 in the Macphail woodlot, Orwell, PEI

INTRODUCTION

The Macphail Woods Ecological Forestry Project is a cooperative effort sponsored by the Environmental Coalition of Prince Edward Island and the Sir Andrew Macphail Foundation. The project combines the protection of a natural area and development and demonstration of management techniques promoting forest stewardship. Among goals established for this project are:

1. to inventory the bird species found within the Macphail woodlot, and
2. to develop bird identification skills in employees and volunteers.

The bird inventory would be part of a biotic inventory of the woodlot that would gather baseline information on the occurrence and abundance of various plant and animal species. Fostering and developing interest in birds and bird identification skills in the public and volunteers will facilitate future and/or long term monitorinq efforts.

It was with these goals in mind that this project was proposed. The objectives of this project are:

1. develop a bird species list for the woodlot,
2. determine bird species abundance and richness for individual stands or groups of stands within the woodlot,
3. monitor changes in these parameters over time and
4. conduct bird identification field tours for employees, volunteers and the public.

Funding for this project was provided by the Samuel and Saidye Bronfman Family Foundation. Staff support time at Macphail Woods was funded through a variety of federal, provincial, private and corporate sources.

METHODS

All bird species and nests encountered while on the Macphail property would be recorded for development of a bird species list. Bird identification tours were to be conducted between June 1 and July 15, organization of employees, volunteers and informing the public was the responsibility of Gary Schneider (representing the Macphail Woods Ecological Forestry Project).

Structured bird surveys

The unlimited distance point count method (Blondel et al, 1981) was chosen to survey the bird community of the woodlot. This method was modified slightly. Bird species easily detectable at great distances were only recorded when clearly within the woodlot boundaries. In addition, birds observed flying above the canopy level (e.g. gulls, corvids, loons) were not recorded.

Six areas (stands or groups of stands) that represented the entire woodlot were selected for surveying. A point (survey station) was located in each area such that it was at least 105 meters from the woodlot boundary and 225 meters from any other point (see Figure 1 for point locations within the Macphail woodlot).

At each point the observer would allow birds to calm after arriving at the point. Then for ten minutes every bird seen or heard and its activity (i.e. singing and calling) would be recorded, notwithstanding the above exceptions. Observations were recorded on a map sheet (Figure 1) to help track moving birds and avoid duplication. Point number, date, replication number, and weather condition estimates, based on personal observations and weather reports, were also recorded on the map sheets.

Surveys were to be conducted between May 15 and July 4, depending upon bird migration timing. Surveys were to be conducted between one half hour before sunrise and approximately 10 a.m., depending upon the conditions each day. No surveys were to be conducted during continuous periods of precipitation, when wind conditions exceeded approximately 15 km/hour or when singing activity was noticeably reduced. Each point was to be surveyed three times.

Mapped observations were interpreted to determine the number of pairs of each species. Singing males were used as the primary indicator of pairs. For example, a count of four singing males represented 4 pairs of that species. Further, a count of 3 singing males and two calling individuals or three singing males and one observed female and a calling individual, represent three pairs for each scenario. In the absence of singing males, calling or observed individuals would represent a pair. Calling frequency is generally less then the frequency of singing, generally making it impossible to determine the number of birds calling. In addition, calling birds cannot be identified by sex. Thus, calling birds represented one pair regardless of the number of calls heard for one species. Likewise, several separate visual observations in the absence of singing males represented one pair.

For each bird species an index of abundance was determined for each survey point (total number of pairs observed divided by number of surveys done at that point). An average abundance index for each bird species was calculated by averaging the abundance indices over all points. Differences between yearly abundance indices were tested by utilizing a Variance Ratio Test and then a 2-Sample l-Test. Total species richness of a point was represented by the number of species recorded on all surveys of that point. The mean species richness was calculated by averaging the number of species recorded per survey of each point. A bird community diversity index was calculated for each point, utilizing Shannon's Formula of General Diversity (Zar, 1974). This index is influenced by the total number of species and the distribution of individuals among these species.

All species recorded during surveys contributed to development of a bird species list.

RESULTS AND DISCUSSION

Approximately thirty-seven hours, during 5 days between June 2 to 18, 1995, were logged in the Macphail woodlot. Structured bird surveys were attempted on June 3, 4, and 18. Bird identification tours/workshops were conducted on June 3, 4, 17 and 18.

No new bird species were added to the Macphail Woodlot bird list, leaving the total count at 71 (see Appendix I for a bird species list based on data for all years). In 1995, 67 active nests of 27 bird species were found (see species with asterisks in Table 1). This brings the total to 34 for bird species whose nests have been found in the Macphail Woodlot.

Bird Identification Tours

Seven tours were conducted. Morning and evening tours were conducted on June 3, 4 and 17 and only a morning tour on June 18 for a total of 15 hours ranging from one to three hours per tour. Tours started at 10 a.m. and 6 p. m. More than sixty volunteers/ employees attended the tours (some participated on more than one tour). Bird behaviour, ecology, identification tips (both for auditory and visual observations), and individual bird species ecology and biology were discussed.

Structured Bird Surveys
General

Eighteen surveys were conducted on six points. Surveys occurred on June 3, 4 and 18. Points were located throughout the woodlot, at the same locations as in 1993 and 1994 (Figure 2). Refer to the 1993 report for descriptions of each point.

A total of 47 species were observed over all points (see Table 1 for species list and abundance indices). This is similar to the number of species observed in 1993 and 1994 (48 and 45 respectively, see Appendix II and III).

No commonly encountered species in 1993 or 1994 was absent in 1995. In fact of the six most abundant species in 1993 and 1994 were also the six most abundant in 1995.

Bird Community Composition

The bird community composition and number of species observed in all years of the surveys are similar to that found by Sabine and Makepeace (1990) for a series (varying age) of tolerant hardwood and old field white spruce standtypes on PEI. However, Sabine and Makepeace (1990) found more bird species in their series of white spruce stands of varying development stages than was found in the Macphail woodlot. However the area sampled by Sabine and Makepeace was much larger than the Macphail woodlot. The number of bird species is positively related to the area sampled.

The black-throated blue warbler is conspicuous in its absence. This species is not rare on PEI or the maritimes (Erskine, 1992). Suitable habitat appears to exist at the Macphail woodlot but for three years no black-throated blue warblers have been observed. This species is usually associated with hardwood dominated standtypes (immature evenaged to unevenaged) that have a well developed understory that includes some coniferous plant species (Bent 1961; Erskine, 1992; Freedman et al 1981; Probst et al 1992; Webb et al 1977). Reasons for the complete absence at the Macphail woodlot is not readily apparent. The blackthroated blue warbler could be responding to landscape level habitat availability/distribution or the habitat at Macphail's may not be suitable for site specific reasons. Black-throated blue warblers have been found to be area sensitive in other geographic areas (Robbing et al 1979). Other bird species that are considered by some to be area sensitive commonly occur at Macphail's (for example ovenbirds, black and white warblers and red-eyed vireos). The Macphail woodlot is approximately 30 hectares of a 55 hectare forested area. The closest forested area is approximately 690 meters away and the landscape surrounding the Macphail woodlot is agriculturally dominated almost completely. Landscape level affects should not be ruled out.

Nine bird species were found at all six points. Of these species only the American robin is generally considered a habitat generalist. The fact that the other species were found at all points probably reflects the small number and relative area of different forest types that occur within the Macphail woodlot.

The total number of species per point and bird community diversity in 1995 showed the same trends as in 1993 and 1994 (Table 2) .

In 1995 there was a partial rebounding of species richness. In 1994 species richness was reduced substantially on all points except point 3 and 6. Points 1 2 and 5 increased in species richness in 1995. For all indices of bird community size and diversity point 6 showed little variation between 1993 and 1994 but in 1995 there was a reduction of bird community size and diversity. The other 4 points (not including #3) all show changes of various size (+8 to +28 for total species richness).

The occurrence of low abundance species accounts for the changes in species richness and most of the variation in community diversity. The occurrence of these species is probably due to the sampling technique and to real changes in abundance of those species. There was no obvious cause of these changes. In 1993 there was an obvious spruce budworm outbreak throughout the woodlot (personal observation). Outbreaks of spruce budworm are known to attract many bird species (Morse, 1978). In 1994 and 1995 there did not appear to be a budworm outbreak, but budworm abundance and distribution in the Macphail woodlot were not measured. The stands that appeared to have the budworm infestation in 1993 appeared to be suffering or have suffered die back (leaders and branches dicing and dead). The breeding season of 1993 was thought to be a poor breeding success year (Erskine, 1993) and if true could have contributed to the observations above. The influence of factors influencing bird populations that occur on the wintering and migration grounds could also have contributed to the changes observed in species richness.

Table 2. Total bird species richness, mean bird species richness, and bird community diversity index for six survey points, surveyed in 1993, 1994 and 1995 in the Macphail woodlot, Orwell, P.E.I.

Some species varied greatly in abundance in the woodlot between 1993, 1994 and 1995 (Table 3). A variance Ratio Test revealed that the variance of samples for year to year comparisons of individual species were not significantly different. Variances need to be similar to conduct a t-Test on means. There were no significant changes in abundances between 1994 and 1995. There were many relatively large changes in mean abundance that were not statistically significant. This was mostly due to large variability in the data. Many of these changes can be considered real (actual differences in abundance), because there is almost complete coverage of the Macphail woodlot by survey points and the survey technique is constant year to year.

There are few obvious trends in abundance for almost all species. Two species do show trends. The black and white warbler declined and the blackburnian warbler increased during the three year period.

The breeding bird survey (BBS) (Price et. al. 1995) for the years 1984 to 1993 shows a non-significant decline (-7.21) in population for the black and white warbler. For the blackburnian warbler a significant (p These changes reported in the BBS are applicable to the area sampled by BBS survey routes. This is generally a large sample area encompassing most of the breeding range for some species. Changes observed for the Macphail woodlot are very local in application and should not be extrapolated to a larger area. There are no other similar projects being conducted in the maritimes to compare with the results of this study. The BBS comparison is used to illustrate that there are other factors influencing overall population size of various species. Trends seen at Macphail may result from local or larger scale influences.

Table 3. Mean abundance (over all points) and 95% Confidence Interval (CI) for selected bird species in the Macphail woodlot, 1993,1994 and 1995, Orwell, P.E.I.

* = means are different P c 0.10
** = means are different P c 0.05
*** = means are different P c 0.05

Individual Points

The distribution of species and abundances have remained relatively stable point to point over the three survey years. Table 4 illustrates the pattern for Ovenbird, magnolia warbler and white-throated sparrow. For example, White-throated sparrow has consistently been more abundant at points 5 and 6, especially n''mh~o' f:;

Points 1 to 4 were dominated by northern parula, blackthroated green warbler, ovenbird, blackburnian warbler, magnolia warbler and red-eyed vireo (Table 1). All of these species, except magnolia warbler, have been found to be dominate components of bird communities in mature hardwood areas on Prince Edward Island (Sabine, 1989, Sabine and Makepeace, 1990). Many authors have also found these species in hardwood dominated areas in other locales (Bent 1961; Chadwick et al 1986; Freedman et al 1981; Probst et al 1992; Webb et al 1977). The magnolia warbler is a bird associated with young softwood development stages. Sabine and Makepeace (1990) found these warblers to be most abundant in eight to fifteen year old regenerating white spruce and scarce in their hardwood dominated areas. Within the Macphail woodlot magnolia warblers were observed in association with dense areas of softwood regeneration that was present throughout the hardwood dominated areas.

Table 4. Abundance indices for three bird species over six survey points for 1993, 1994 and 1995 in the Macphail woodlot. Orwell. PEI.

Point number five was dominated by red-eyed vireo, northern parula, blackburnian warbler, magnolia warbler and mourning warbler. Of these species magnolia warbler, northern parula and blackburnian warbler are considered to be typical of softwood dominated forest. The red-eyed vireos found in this old field white spruce stand were closely associated with yellow birch plantations and areas of natural deciduous regeneration.

Mourning warblers were associated with ground cover available throughout the stand. Other bird species, typically only found in softwood dominated areas, were also found in this stand. For example bay-breasted warblers and evening grosbeak were observed.

Point number six was dominated by alder flycatchers, magnolia warblers, northern parula, yellow-rump[ed warbler, Tennessee warblers and white-throated sparrows. All of these species are typical of early development stage stands (young age).

The mean number of species of point number six (see Table 2) was the highest of all six points surveyed. This point also had a relatively high bird community diversity, although it was smaller than in 1993 and 1994. The large number of species and high community diversity was probably influenced by the high variability of vegetation structure in the area represented by this point. There was a pond, mature softwood and hardwood areas, grassy areas, alders and different age softwood plantations. Within the woodlot this is the only area of young, early development stage stands meaning bird species such as common yellowthroats, lincoln's sparrows and alder flycatchers could only be found here. The diversity of bird species in a given area is strongly associated with vegetation structure (MacArthur and MacArthur, 1961; Willson 1974).

Casual observations

Twelve bird species were observed during non-structured surveys. Six species generally do not occur in forest habitat types (such as bobolink, barn swallow and savannah sparrow) the rest were species occurring at very low abundances and are not well surveyed by the point count survey technique (such as black duck, belted kinqfisher and american qoldfinch).

Summary

A total of fifty nine bird species were observed within the Macphail property in 1995. No new bird species were added to the total species list leaving it at 71. Approximately 85` of these species were associated with various forest stand types.

The six survey points represent three different general stand types; Hardwood dominated mature, softwood dominated mature and mixed regenerating. Each of these standLypes contributed bird species to the bird community of the Macphail woodlot that would not be present without that stand type.

The Macphail woodlot continued to support a diverse and abundant collection of bird species. No common species in 1993 and 1994 were absent in 1995. There were no substantial changes in abundance of some individual bird species. Some trends appeared to be occurring such as a decline of black and white warbler and an increase of blackburnian warbler abundances.

Comparisons to other areas was not possible. Readers should be cautioned that changes within the breeding bird community observed at the Macphail woodlot can not be extrapolated to a larger geographic area.

LITERATURE CITED

Blondell, J., C. Ferry, and B. Frochet. 1981. Point counts with unlimited distance. Studies in avian biology 6:414-420.

Chadwick, N.L.; Progulske, D.R. and J.T. Finn. 1986. Effects of fuelwood cutting on birds in southern New England. Journal of Wildlife Management 50(3):398-405.

Darveau, M., J.L. DesGranges, and G. Gauthier. 1992. Habitat use by three breeding insectivorous birds in declining maple forests. The Condor 94:72-82.

Erskine, A.J. 1992. Atlas of Breeding Birds of the Maritime Provinces. Nimbus Publishing Limited. 270pg.

Erskine, A.J. 1994. Maritimes Nest Records Scheme: 34th annual report. 2 Opp .

Freedman, B., C. Beauchamp, I.A. McLaren, and S.I. Tingley. 1981. Forest management practices and populations of breeding birds in a northern hardwood forest in Nova Scotia. Can. Field-Nat. 95:307-311.

MacArthur, R.H. and J.W. MacArthur. 1961. On bird species diversity. Ecoloqy 42: 594-598.

Makepeace, S. 1989. Avian surveys of managed and unmanaged forest stands in the Montague River Watershed and Forest Hill

Wildlife Manaqement Area. unpub. report. 58pp.

Morse, D.H. 1978. Populations of bay-breasted and Cape May warblers during an outbreak of the spruce budworm. Wilson Bulletin 90-404-413

Peterjohn, B.G. and J.R. Sauer. 1993. North American Breeding Bird Survey Annual Summary. Bird Populations Vol. 1.

Price, J., S. Droege and A. Price. 1995. The summer atlas of North American birds. Academic Press Limited. 364pg.

Probst, J.R., D.S. Rakstad, and D.J. Rugg. 1992. Breeding bird communities in regenerating and mature broadleaf forests in the USA Lake States. For. Ecol. Manaqe. 49:43-60.

Robbins, C.S. 1979. Effect of forest fragmentation on bird populations. pp. 198-212 in R.M. DeGraaf and K.E. Evans, eds. management of northcentral and northeastern forests for nongame birds. U.S. For. Serv. Gen. Tech. Rep. NC-51.

Sabine, D.S. 1989. Avifaunal surveys of managed and unmanaged forest stands in central and western Prince Edward Island. Forestry Canada unpub. rep. FRDA SD-002. 51pp.

Sabine, D.S. and S. Makepeace. 1990. Surveys of breeding bird communities in managed and unmanaged forest stands on Prince Edward Island. ForestrY Canada unpub. rep. FRDA SD-006. 86pp.

Webb, D.L., D.F. Behrend, and B. Saisorn. 1977. Effect of logging on songbird populations in a northern hardwood forest. Wildl. Monogr. 55. 35pp.

Willson, M.F. 1974. Avian community organization and habitat structure. Ecology 55:1017-1029.

Zar, J.C. 1974. Biostatistical analysis. Prentice Hall Inc. 416pg.

Birds
American black duck - Annas rubripes 
green-winged teal - Annas crecca 
american kestrel - Falco sparverius 
sharp-shinned hawk - Accipiter striatus 
northern goshawk - Accipiter gentilis 
ruffed grouse - Bonasa umbellus 
mourning dove - Zenaida macroura 
great horned owl - Bubo virginianus 
barred owl - Strix varia 
ruLy-throated hummingLird - Archilochus colubris 
belted kingfisher -Megaceryle alcyon 
northern flicker - Colaptes auratus 
yellow-bellied sapsucker - Sphyrapicus varius 
downy woodpecker - Picoides pubescens 
hairy woodpecker - Picoides villosus 
eastern wood-pewee - Contopus virens 
yellow-bellied flycatcher - Empidonax flaviventris 
olive-sided flycatcher - Nuttallornis borealis 
least flycatcher - Empidonax minimus 
blue jay - Cyanocitta cristata 
black-capped chickadee - Parus atricapillus 
boreal chickadee - Parus hudsonicus 
brown creeper - Certhia familiaris 
red-breasted nuthatch - Sitta canadensis 
ruby-crowned kinglet - Regulus calendula 
golden- crowned kinglet - Regul us sa trapa 
winter wren - Troglodytes troglodytes 
American robin - Turdus migratorius 
Swainson's thrush - Catharus ustulatus 
hermit thrush - Catharus guttatus 
red-eyed vireo - Vireo olivaceus 
solitary vireo - Vireo solitarius 
northern parula - Parula americana 
black-throated green warbler - Dendroica virens 
black and white warbler - Dendroica varia 
black-throated blue warbler - Dendroica caerulescens 
magnolia warbler - Dendroica magnolia 
yellow-rumped warbler - Dendroica corona ta 
Canada warbler - Wilsonia canadensis 
chestnut-sided warbler - Dendroica pensylvanica 
Cape May warbler - Dendroica tigrina 
bay-breasted warbler - Dendroica castanea 
Blackburnian warbler - Dendroica fusca 
American redstart - Setophaga ruticilla 
yellow warbler - Dendroica petechia 
Tennessee warbler - Vermivora peregrine 
Nashville warbler - Vermivora ruficapilla 
mourning warbler - Oporornis philadelphia 
common yellowthroat -Geothlypis trichas 
ovenbird - SeJurus aurocapillus
common grackle - Quiscalus quiscula 
red-winged blackbird - AgelaJus phoeniceus 
bobolink - Dolichonyx oryzivorus 
European starling - Sturnus vulgaris 
evening grosbeak - Coccothraustes vespertinus 
American goldfinch - Carduelis tristis 
pine siskin - Carduelis pinus 
white-winged crossLill - Loxia leucoptera 
rose-breasted grosbeak - Pheuticus ludovicianus 
northern junco - Junco hyomalis 
brown-headed cowbird - Molothrus ater 
purple finch - Carpodacus purpureus 
white-throated sparrow - Zonotrichia albicollis 
chipping sparrow - Spizella passerine 
swamp sparrow - Melospiza georgiana 
song sparrow - Melospiza melodia 
Lincoln's sparrow - Melospiza lincolnJi 
savannah sparrow - Passerculus sandwichensis

plants
red spruce - Picea rubens 
black spruce - Picea mariana 
white spruce - Picea glauca 
jack pine - Pinus banksiana 
sugar maple - Acer saccharum 
yellow birch - Betula allegheniensis

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