Jeff Port

Small Mammal Habitat Preferences in a Patchwork of Adjacent Reconstructed Grasslands Subject to Semiannual Burns

This study used small mammal capture-recapture methods within a mosaic of side-by-side prairie reconstructions to evaluate the relationship between floristic diversity, the effect of prescribed burns, and habitat use. This unique 10.4 ha study of opportunity consisted of multiple plots of three habitat types: low floristic diversity exotic cool-season grasses (CSG), low floristic diversity grass plantings dominated by native warm-season grasses (WSG), and floristically diverse, mixed prairie (MP) plantings with > 45 species of forbs. Data for calculating small mammal abundances (new captures/trap effort) were determined by trapping in August following spring burns in 2002 and 2004, and unburned years in 2003 and 2005. Fire-positive species (meadow jumping mice, Peromyscus spp.) preferred fields with a more open understory (MP plantings), and a reduced thatch thickness and leaf litter layer (burned fields). Fire-negative species (meadow voles, northern short-tailed shrews) populated all restorations (CSG, WSG, MP plantings) but only during the unburned years when the fields provided a high density of vegetative cover. Even though the distinct floristic diversity found within the three reconstruction types influenced small mammal foraging preferences, the effect of semiannual burns on floristic structures had a noteworthy impact on their distributions. The results of this study demonstrate an important take home message for restoration practitioners: techniques that promote differences in structural characteristics are just as important as creating plantings with high floristic diversity.

BEHAVIORAL ADAPTATIONS FOR BREEDING IN ARBOREAL-NESTING SPECKLED TEAL

Abstract Ground-nesting is usual among the about fifty species of dabbling ducks (genus Anas), but a few southern hemisphere species prefer arboreal sites. One such arboreal-nesting species, the South American Speckled Teal (Anas flavirostris flavirostris), is believed to have evolved from a ground-nesting ancestor, represented today by the closely related Green-winged Teal (A. carolinensis) of North America. We studied the breeding biology and behavior of Speckled Teal in Buenos Aires province, Argentina, in an attempt to identify adaptations associated with arboreal nesting. In this region, Speckled Teal prefer to nest in cavities in the stick nests of Monk Parakeets (Myiopsitta monachus). Inter- and intraspecific competition for cavities was intense. Parakeets remained near the nest site year round, aggressively defending occupied cavities and forcing teal to compete with one another for possession of abandoned cavities. Male Speckled Teal helped their mates to obtain and hold nest sites by defending sites against other pairs. Males also accompanied broods and assisted in parental care. Although courtship occurs year round and extrapair courtship by males is common, competition for mates and the need for male assistance in acquiring nest sites limits the opportunities for polygyny in this population. Site fidelity of nesting females was very high; 19 of 22 returned the following year. The prevalence of courtship on land and inclusion of Point display in the repertoire are interpreted as behavioral adaptations associated with arboreal nesting.

Cooperative Breeding at a Nest of Slaty-backed Nightingale-Thrushes (Catharus fuscater)

ABSTRACT Our observations on the reproductive habits of the Slaty-backed Nightingale-Thrush (Catharus fuscater) were made at a single nest between 2–12 November 2009 at an elevation of 2,050 m, in the vicinity of the Yanyacu Biological Station and Center of Creative Studies (00o 36′ S, 77o 53′ W), 5 km west of Cosanga (Napo Province, northeastern Ecuador). During the first 3 days following hatching, the only adult which provisioned nestlings was a color-banded female. Beginning with day 4, however, we observed five other individuals bringing food to the nest, including three color-banded males, one unmarked male, and one unmarked individual presumed to be female. The last two birds and one of the banded males were sexed using morphological differences, the remaining banded individuals were sexed molecularly. Most (72%) of provisioning visits to 4–9 day old nestlings were made by the color-banded female which also incubated the eggs. Our observations suggest the existence of a potentially complex cooperative breeding system in Slaty-backed Nightingale-Thrush.

The Effect of Floristic Composition on Bird Communities in a Set of Four Grassland Reconstruction Types

With most native prairie now lost, focus has turned to reconstructing grasslands with the aim of replicating ecosystem function for grassland fauna and flora. We report the results of a seven-year study (2008–2014) on the use of four floristically different prairie reconstructions by grassland birds. The study was conducted near Austin, Minnesota on a 64.75-ha (160-acre) Wildlife Management Area. Prairie reconstruction was implemented in 2005 on land previously used for row crops, and the study site consisted of eight identically sized (4.5 hectare), side-by-side of replicates of four distinct planting mixes. We used fixed-point transect surveys to document differences in the number of species and individuals of grassland birds between plot types. We found differences in the abundance of individuals and diversity of bird species between plot types, with fewer bird species and individuals present in lower plant-diversity plot types compared to higher plant-diversity plots. Eighteen species of grassland birds were recorded on the site, with none exclusively restricted to any plot type. Grassland obligate bird species, including Sturnella magna (Eastern Meadowlark), Dolichonyx oryzivorus (Bobolink), Ammodramus savannarum (Grasshopper Sparrow), Ammodramus henslowii (Henslow’s Sparrow), and Passerculus sandwichensis (Savannah Sparrow), were documented using low floristic diversity, cool-season grass plots. Other species, such as Spiza americana (Dickcissel), Melospiza melodia (Song Sparrow) and Spinus tristis (American Goldfinch), showed preferences for high diversity, forb dominated plots. Our results indicate that planting a mosaic of restoration mixes may be the most successful at attracting and retaining the highest diversity of bird species.

The Spotted Barbtail (Premnoplex brunnescens): male and female parental effort during the nestling period

ABSTRACT We document male and female roles in nestling care of Spotted Barbtails (Premnoplex brunnescens) including feeding rates and temporal patterns of provisioning by each sex. Using 128.5 hrs of video from color marked and molecularly sexed individuals at two nests, we confirm that both sexes of Spotted Barbtail provision nestlings. Spotted Barbtail females in our study invested more heavily in nestling care than males, making 73% of feeding visits. Females also visited the nests nearly twice as often as males, averaging 1.24 visits/nestling/hr compared to 0.69 visits/nestling/hr for males. While Spotted Barbtails exhibit many of the features assumed to favor social and genetic monogamy, intriguing aspects of nest building and incubation leave open the possibility that this species is unusual among the Furnariidae and utilizes extra-pair matings as a part of the reproductive strategy.