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ABSTRACT BOOK Listed alphabetically by last name of presenting author AOS 2019 Meeting 24-28 June 2019 ORAL PRESENTATIONS Variability in the Use of Acoustic Space Between propensity, renesting intervals, and renest reproductive Two Tropical Forest Bird Communities success of Piping Plovers (Charadrius melodus) by fol- lowing 1,922 nests and 1,785 unique breeding adults Patrick J Hart, Kristina L Paxton, Grace Tredinnick from 2014 2016 in North and South Dakota, USA. The apparent renesting rate was 20%. Renesting propen- When acoustic signals sent from individuals overlap sity declined if reproductive attempts failed during the in frequency or time, acoustic interference and signal brood-rearing stage, nests were depredated, reproduc- masking occurs, which may reduce the receiver’s abil- tive failure occurred later in the breeding season, or ity to discriminate information from the signal. Under individuals had previously renested that year. Addi- the acoustic niche hypothesis (ANH), acoustic space is tionally, plovers were less likely to renest on reservoirs a resource that organisms may compete for, and sig- compared to other habitats. Renesting intervals de- naling behavior has evolved to minimize overlap with clined when individuals had not already renested, were heterospecific calling individuals. Because tropical after second-year adults without prior breeding experi- wet forests have such high bird species diversity and ence, and moved short distances between nest attempts. abundance, and thus high potential for competition for Renesting intervals also decreased if the attempt failed acoustic niche space, they are good places to examine later in the season. Lastly, overall reproductive success the way acoustic space is partitioned. Here we exam- and daily nest survival were lower for renests than first ine the fine-scale use of acoustic space and the rele- nest attempts throughout the breeding season. Further- vance of the ANH in two montane tropical wet forest more, renests on reservoirs had reduced apparent breed- bird communities that vary significantly in bird species ing success unless the predicted amount of habitat on richness but have similar overall bird abundance. The reservoirs increased within the breeding season. Our re- first location was within a large forest fragment near the sults provide important demographic measures for this Las Cruces Field Station in southern Costa Rica and the threatened species as well as implications for predation- second in Hakalau Forest National Wildlife Refuge on and water-management strategies. Altogether, renest- the island of Hawaii. Using automated sound recorders ing may not be an effective reproductive strategy for at replicate locations in each area, we found that bird Piping Plovers breeding in the Northern Great Plains. vocalizations in species-poor Hawaii had significantly more temporal overlap than species-rich Costa Rica. Similarly, we found that vocalizations of bird species Impacts of the December 2016 to August 2017 Bo- in Hawaii contained a significantly higher percentage goslof Island Eruption Event on a Major Alaskan of overlapping frequencies than those in Costa Rica. Seabird Colony This different use of acoustic space between the two bird communities, with partitioning being greater in the Nora A Rojek, Gary S Drew species-rich community, provides support for ANH in Costa Rica but not Hawaii and is likely due to selection Bogoslof Island, managed by the Alaska Maritime Na- to reduce heterospecific signal overlap. tional Wildlife Refuge, is an important breeding site for seabirds and marine mammals in the southeastern Bering Sea. Importantly, it includes one of only four Can Renesting Be an Effective Reproductive Strat- major breeding sites for red-legged kittiwakes (Rissa egy and How Does it Influence Conservation of a brevirostris). Periodic eruptions of Bogoslof volcano Threatened Shorebird Species? result in a changing landscape and alters seabird nest- ing habitat. The most recent event of 64 eruptions Rose J Swift, Michael J Anteau, Megan M Ring, Dustin over eight months increased island area by 300% and L Toy, Hillary R Wagner, Mark H Sherfy buried vegetation and soil. Continuous eruptive activ- ity in 2017 likely prevented seabirds from successfully Upon reproductive failure, many bird species may make breeding that season. In August 2018, a site visit de- a secondary attempt at nesting, hereafter renesting. tected the presence of most seabird species known to Renesting may be an effective strategy to maximize cur- previously occupy the island but with little evidence of rent and lifetime reproductive success, but individuals successful breeding except by glaucous-winged gulls face uncertainty in the probability of success because (Larus glaucescens). Nest building species, such as nests initiated later in the breeding season often have kittiwakes (Rissa spp.) and cormorants (Phalacroco- reduced nest or brood survival. We evaluated renesting rax spp.), lost access to nest materials. The main pre- 2 Anchorage, Alaska, USA Abstract Book eruption breeding area for murres (Uria spp.) was al- Decadal Shifts in Patterns and Benefits of Nesting tered and only a small number of eggs and chicks were Near Territorial Predators by Tundra-Nesting Sea observed. Tufted puffins (Fratercula cirrhata), which Ducks typically rely on soil and vegetation for burrows, lost all nesting habitat; birds attempted to dig new burrows Micah W Miller, James R Lovvorn, Nathan Graff, Nee- but could not excavate far into hard surface layers and sha Stellrecht, Lori T Quakenbush, David E Safine unconsolidated subsurface layers. Because most long- lived seabirds exhibit colony site fidelity, we expected Birds may nest near territorial predators, presum- them to return with limited impact on population num- ably because benefits of protection exceed risks bers. However, given that no fine ash was deposited of nest depredation by host predators. Tundra- during the eruptions, soil development is expected to nesting sea ducks may nest near territorial Pomarine be prolonged. Species relying on vegetation for nests Jaegers (POJA, Stercorarius pomarinus) or Snowy Owls and soil for burrows may be constrained from breeding (SNOW, Bubo scandiacus) for defense against Arctic until soil develops. foxes (Vulpes lagopus). Lemming-specialist POJA and SNOW apparently nest in higher densities in years of moderate to high lemming abundance while foxes shift from lemmings to bird- and egg-focused diets, thus im- pacting sea duck nest survival. Anthropogenic reduc- Measuring Impacts of Non-Native Species on tion of foxes may influence nesting behavior of both sea Cavity-Nesting Birds at the Continental Scale ducks and territorial avian predators. During the 1990s, threatened Steller’s eiders (STEI, Polysticta stelleri) Robyn L Bailey, Holly A Faulkner, Victoria Y Martin, nested close to avian predators, but this relationship was Tina B Phillips, David N Bonter less defined during the 2010s when foxes were con- trolled to increase nest survival. Three other sea duck Invasive species are a threat to global biodiversity. In species (King Eider, Somateria spectabilis; threatened North America, nest site competition from invasive Spectacled Eider, S. fischeri; and Long-tailed Duck, C. cavity-nesting birds can limit the opportunities for suc- hyemalis) also showed tendencies to nest near POJA cessful nesting by native birds. We sought to quan- and SNOW during the 2010s. Sea ducks appeared to tify the relative impacts of European Starling (Stur- avoid nesting near Parasitic Jaegers (Stercorarius para- nus vulgaris) and House Sparrow (Passer domesticus) siticus), a common nest predator. No benefit to appar- on reproduction by native cavity-nesting birds. We ent nest success was measurable through these associa- administered a survey to citizen scientists who main- tions. In one subarea, apparent POJA nesting densities tain nest boxes for birds in the United States and declined greatly from the 1950s to the 2010s, perhaps in Canada. Respondents (N = 874) monitored an av- concert with declines in lemming densities. Widespread erage of 56.87 ( 1.31 SE, range 1494) nest boxes declines in lemming abundance may diminish the rela- in 2018. Nearly one in three observers documented tionships among sea ducks, territorial avian predators, a non-native species usurping the nest of a native and foxes. This issue is especially important for STEI, species (30.5%). For people reporting any nest usurpa- which typically have shown minimal breeding effort in tion activity, rates of nest usurpation varied by host low lemming years when POJA and SNOW were absent species (range: 028%). House Sparrows were more or at very low densities. likely than European Starlings to usurp the nests of bluebirds (Sialia sp.), Tree Swallows (Tachycineta bi- color), House Wrens (Troglodytes aedon), and chick- Consequences of Nest Outcome on Investment into adees (Poecile sp.), whereas European Starlings were Later Broods by Gray Catbirds more likely to usurp the nests of American Kestrels (Falco sparverius; paired t-tests comparing usurpation Lucas J Redmond, Jordan I Haq, Duncan Noble, Dono- rates by House Sparrows and European Starlings, all P van Ricco < 0.05). Purple Martins (Progne subis) were equally likely to have nests usurped by starlings and sparrows. Birds generally exhibit low levels of fecundity while Our results suggest that House Sparrows and European heavily investing into individual offspring, examples of Starlings are likely impacting reproduction