Bird Habitat of the Sicily Island Hills

Posted: January 4, 2010 in Homepage
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This post is rather long in content and details. But if you are really interested in birds,  including but not limited to birds within the Sicily Island Hills, I challenge you to hang in there and read the post in its entirety.

I am friends with a lot of birders in northeast Louisiana but it has been my experience that most birders do not frequent the Sicily Island Hills. The reason for the lack of birding may be due to distance. However, to a true birder I don’t believe distance would be a hindrance.

A birding friend of mine from Hebert once drove to Big Bend National Park to look for the Colima Warbler. She sighted the bird and once she added it to her life list she immediately returned to northeast Louisiana.

Perhaps lack of knowledge about the Sicily Island Hills by most of the general populace, birders included, may be the culprit. If that is the case, I hope to rectify that situation.

Maybe the birding isolationism with regards to the Sicily Island Hills could be caused by the abundance of other opportunities in our state. There are quite a number of places in Louisiana with many varied habitats that lend themselves to birding such as coastal, marsh, riparian, and various forests, just to name a few. Many of these places are well documented and perennially provide outstanding bird sightings.

Once you visit these hills you quickly observe thick stands of trees. Conceivably, the dense forest with steep hills is less desirable to birders. But as you will find out in this post on SIH birding habitat, and a subsequent post soon to follow on bird observations at SIH,  there are a  myriad number of birds to be found for your birdwatching enjoyment within the hills of Sicily Island. Not only are there opportunities to observe birds in the forest here, but the sky above the forest offers possible sightings of eagles and hawks.

Looking North

The catfish ponds in the distance north of the Sicily Island Hills could increase sightings of birds of prey as well.

In 2005 Michael J.Baranski  a then graduate student in the Department of Biology at the University of Louisiana-Monroe published his thesis entitled “Avian Responses to Forestry Practices at Two  Wildlife Management Areas in Northeast Louisiana”. I am indebted to Mike for his hard work, the result of which was his thesis, and for his kindness and willingness to share his experiences.

Phenology is the study of the relationship of climate and biological phenomena. For example, in this study the abundance of birds at various seasons of the year was a phenomena of focus.

NTM refers to Neotropical Migrants

Mikes thesis study areas were Buckhorn WMA and Sicily Island Hills WMA.

The difference in species observed, that is a greater number at Buckhorn WMA (165), was accounted for in part by less aquatic and open habitat at Sicily Island Hills WMA (117).

Only site specific information pertaining to Sicily Island Hills WMA is used in this post.

Breeding bird surveys were conducted from April 2003/2004 through the first week of July 2003/2004.

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Excerpts from the thesis of Michael J. Baranski:

The majority of birds present in North America during the breeding season migrate from wintering habitats in the tropics, hence the name Neotropical migrant (NTM).  These attributes differentiate them from migrants in general, which include birds that winter in southern North America but breed in northern North America.

Forest tracts under different management techniques can have different relative abundance and diversity of breeding birds.  Uneven-aged management (group or individual selection) may produce small changes in the bird community due to changes in structural diversity of the vegetation (Dickson and others 1993).  Uneven-aged managed stands contain a higher number of forest interior species, many of great conservation concern, associated with more mature forests with high canopy closure and lower tree density (Webb and others 1977, Annand and Thompson 1997).  In comparison, complete removal of trees from large or even somewhat smaller areas can result in a complete replacement of bird communities from late-successional to early successional assemblages.  Even-aged management (clearcut and shelterwood) may actually hold the greatest species richness, being predominantly populated by species associated with low canopy cover and high sapling density.  Morrison (1992) reported that it is possible to maintain similar bird species diversity and abundance with both even-aged and uneven-aged management techniques if high tree species diversity and other wildlife needs are met.

The understory is important not only for nesting substrate but also for foraging.  Most understory birds will modify their foraging habits when the habitat is altered while other species will completely abandon these disturbed areas (Franzreb 1983).  In areas where the understory was completely removed or heavily reduced during forest management, warblers, such as the Hooded (Wilsonia citrina) and Worm-eating (Helmitheros vermivorum), were nearly absent when compared to tracts with the understory left intact (Rodewald and Smith 2004).

Forest fragmentation can be considered a leading cause of the decline in migratory bird populations.  As fragmentation increases, the ratio of forest edge to interior increases.  It is at these edges, typically forested edge adjacent to non-forested, where interactions such as predation, nest parasitism, and competition are more likely to occur (Ratti and Reese 1988).  Forest-interior birds, which require large tracts of contiguous forest to breed successfully, experience a decrease in nest success due to increases in nest predation and nest parasitism (Wilcove 1985, Andren and Angelstam 1988, Temple and Cary 1988, Hoover and others 1995, Robinson and others 1995).  Fragmentation and its edge effects may ultimately result in the area becoming a population sink for these species (Dickson and others 1993, Donovan and others 1995).

Sicily Island Hills Wildlife Management Area (SIHWMA)

Sicily Island Hills Wildlife Management Area is located in Catahoula Parish (Figure 3) and contains 3,044 ha (7,524 ac) of loblolly-shortleaf pine and upland hardwoods.  It is located adjacent to Boeuf Wildlife Management Area.  Big Creek, which drains nearly all of the uplands, runs throughout the WMA and is a tributary to the Ouachita River which runs along the west boundary along with it’s affluent, the Boeuf River.  The original tract was acquired by the LDWF in 1980 with the purchase of 817 ha (2020 ac) and the donation of 1,682 ha (4,158 ac) from International Paper Company.  The remaining areas were purchased over the next seventeen years with the last acquisition being made in 1997 (Wycoff 1994).

The landscape is very unique for Louisiana and consists of continuous ridges dropping steeply into rocky creek bottoms.  The elevations range from 35 M.S.L to approximately 245 M.S.L. The distinct topographic relief allows for a high diversity of plant and animal communities.   There are four small, clear flowing streams (Big Creek, Little Creek, Coke Creek, and Sandy Bayou) that meander through SIHWMA, totaling approximately 16 km in length.  A 2 ha (5 ac) lake, impounded in the 1960’s, is located on the north end of the area (Wycoff 1994).

SIHWMA is located in the Nature Conservancy’s West Gulf Coastal Plain Ecoregion #41 and is considered a “Dry Pine-Hardwood Flatwoods” (CES203.278) (TNC 2003).  As a natural community in Louisiana, it is considered a “Mixed Hardwood-Loblolly Forest” within the terrestrial mixed evergreen/deciduous forest category.  Rare plant communities found at SIHWMA include “Beech-Magnolia-White Oak/Ironwood/Eastern Hophornbeam-American Holly Forest” and “Loblolly Pine-Southern Red Oak-Black Hickory/Farkleberry Forest” (LNHP 2004).

A majority of the land is covered with an uneven aged class forest with a variety of timber species.  The dominant overstory species of the ridges are loblolly pine (Pinus taeda), white ash (Fraxinus pennsylvanica), southern red oak (Quercus rubra), and white oak (Quercus alba).  At lower elevations and along creek bottoms, species such as American beech (Fagus grandifolia), magnolia (Magnolia grandiflora), sweetgum (Liquidambar styraciflua), black gum (Nyssa sylvatica), and eastern hophornbeam (Ostrya virginiana) are present.  The overall understory is quite sparse, especially along the ridges, but a great variety of species is present.

The predominant soil type is the Lexington-Providence-Bude association with other associations such as Ruston, Grenada, and Calloway also present.  These soils are medium to strongly acidic with low levels of organic matter and plant nutrients.  Evident throughout the area, these soils will erode sometimes to severe degrees.  All soils found in SIHWMA belong to the Loessial Hills group (Wycoff 1994).

Prior to 1980, approximately one-third of the present wildlife management area was heavily logged (clearcut and select harvest) and grazed by livestock.  Specific information on the cuts, clearcut in 1977 and select in 1978 is unavailable. Three small salvage cuts were performed in 1985 due to pine beetle infestations, but since that time, no large scale timber harvests have been scheduled (Wycoff 1994)(Table 2).

Table 2 Timber treatments of SIHWMA

Compartment Treatment Method Date
2 Clearcut 1977
5 Clearcut 1977
9 Clearcut 1977
1 Select Cut 1978
6 Select Cut 1978

SIHWMA contains 11 compartments (Figure 4) with compartments 4 and 8 set aside as natural areas.  There are two private land inholdings located within compartments 7 and 10.

Map Showing Study Compartments

Figure 4. Click on map for clearer, larger image.

(Editor: Purple designates clear cuts. Areas in orange show select cuts. Green areas are natural. The red line delineates the wildlife management area boundary. The white lines separate the distinct study compartments. The two rectangular red bordered areas in the southern half of the wma are privately owned inholdings)

Relative Abundance and Diversity

At SIHWMA, bird abundance varied only slightly between treatments.  It is important to remember that the clearcut and select cut management practices occurred over 25 years ago.  This time frame has allowed natural regeneration of the vegetation to occur.  Actual effects of these types of treatments on the current bird species may be obsolete.  Due to the lack of management and disturbance in the past 25 years, SIHWMA is essentially one contiguous forest containing the same type of habitat.  It is predominantly a closed canopy forest with a limited understory and midstory.

The Acadian Flycatcher and Red-eyed Vireo showed treatment effects.  They were most abundant in the select area and least abundant in the clearcut.  These two species were fairly common throughout SIHWMA, especially the Acadian Flycatcher, due to the mostly contiguous, closed canopy forest with which these species are associated.  The Northern Cardinal was significantly less abundant in the select cut.  It is well known that this species is a habitat generalist, thus significant differences in abundance was unexpected and unexplained.

The most unexpected data were the high numbers of Hooded Warblers that were found throughout SIHWMA.  Surprisingly, this species was the most abundant of any bird recorded during the breeding season.  The Hooded Warbler is a shrub nesting species, and it was unusual to have such high abundance on SIHWMA with its limited understory.  Although, thickets of Arundinaria gigantea were not uncommon, they could potentially be the reason for the high abundance of this species (Pashley and Barrow 1993).

SIHWMA did contain some unique species not typically found on other WMAs in  northeast Louisiana.  The Pine Warbler (Dendroica pinus), which is associated with various Pinus spp. was fairly common throughout the WMA.  Pinus taeda and Pinus echinata were found in all parts of SIHWMA.  The Worm-eating Warbler, a ground-nesting bird and an extremely local breeding bird in Louisiana was observed at SIHMWA at numerous locations.  According to Lowery (1974), this species is associated with deep-gullied, well shaded beech-magnolia woods–a habitat frequently found at SIHWMA.

The Prothonotary Warbler, normally a common songbird of southeastern forests, was only found in one area in very low numbers.  SIHWMA is a dry upland habitat and the lack of water can be attributed to the low abundance of this species.  One aquatic feature that did attract an unusual species was the ephemeral creeks found at the bottom of most ridges.  These creeks provide suitable foraging grounds and nesting substrate for the Louisiana Waterthrush (Seirus moticilla).  Although a nest was never located, breeding pairs were observed outside of survey times at various locations.  This species was not observed very frequently during breeding bird surveys due to the lack of point counts adjacent to creeks.

The absence and low detection of early-successional species was due to the lack of appropriate habitat.  Species such as the Yellow-breasted Chat and Indigo Bunting were almost exclusively recorded during casual observations in open areas associated with a few small ponds located in the northeast corner of the property.  The Brown-headed Cowbird, which is more closely associated with open or edge habitat, was also fairly uncommon in all four treatment areas.

SIHWMA is a homogeneous habitat and vegetation variables were very similar between treatments.  Most species present were associated with either a mature, closed canopy forest or a dry, upland habitat.  Specific correlations between vegetation and species abundance could not be made.

Phenology

Overall, 118 species were observed at SIHWMA.  The lack of habitat diversity could explain the low number of birds utilizing this area.  The absence of aquatic habitat appears to be a major factor in the lower number of bird species when compared to BWMA.  Only a few species of waterfowl and sandpipers were observed.   Many of these species were only observed once or twice.  At times, it was difficult to locate some of the more common species such as the Great Egret (Andrea alba) and Great Blue Heron (Andrea herodias).  Seven species of warblers were found to use this area as a stop-over site during migration.

On several occasions Cooper’s Hawks (Accipiter cooperii) were observed darting through the forest midstory and it was probable that they were using this area as breeding grounds.  Chuck-wills-widow (Caprimulgus carolinensis), a common breeder of upland habitats with a mixture of pines and oaks (Lowery 1974), could be heard calling most nights during breeding season.  During the winter months, one could locate a Bald Eagle (Haliaeetus leucocephalus) almost at any time soaring over SIHWMA.  At the largest pond, Bald Eagles were frequently observed perched in one of the surrounding tall pines.  Only once were they witnessed utilizing the pond as a food source, and that was by a juvenile bird.  It is thought that a nearby catfish farm sustained these birds during the winter months and they utilized SIHWMA as a roosting ground.  SIHWMA is located approximately only 50 km southwest from BWMA, but the difference in abundance of the Barred Owl is quite apparent.  The Barred Owl prefers more a swamp type habitat (Kauffman 2000) and is much less common in a dry, upland habitat of SIHWMA.

According to the Louisiana Breeding Bird Atlas (Wiendenfeld and Swan 2000), 73 species are identified as possibly breeding in Catahoula Parish.  During the phenology study, 58 species of birds were observed during safe dates.  Many of the species not found are associated with open habitat or aquatic habitat.  A total of 10 species observed at SIHWMA are currently on the National Audubon Society Watch List for North America.  Seven species, different from the North America list, are currently on the Louisiana Audubon Society Watch List.

Avian Conservation Significance

The natural areas had the highest avian significance among the treatments (219.77) and the clearcut had the lowest (173.54).  This suggests that there may still be some negative effects from the clearcut, which resulted in an even-aged class forest.  In this instance an unmanaged area may hold a higher conservation significance than even-aged management sites.

There is no single silvicultural treatment or forest type that best suits all bird species.  As evident in this study and several others (Annand and Thompson 1997, Dickson 1978), numerous species are associated with specific habitat types, from early successional to late successional, as well as even-aged to uneven-aged treatment types

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I would like to once again express my appreciation to Mike Baranski for his willingness to allow excerpts from his work to be displayed on this post.

A post on bird observations  at Sicily Island Hills by Michael Baranski  (2004) and Michael Seymour (2008) will be appearing in the near future.

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