Size and Composition of Foraging Flights in Two Species of Piscivorous Colonial Birds: Limited Evidence for Intra- or Interspecific Information Transfer

Doucette, Jennifer L.; Kjoss, Victoria A.; Somers, Christopher M.

doi:10.2174/1874453200801010048

Cited by 2 publications

(2 citation statements)

References 36 publications

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“…On Last Mountain Lake, depth and aquatic habitat variation along the length of the lake likely influenced where birds foraged to some degree. Both cormorants and pelicans generally forage in shallow water, and will move to follow ephemeral sources of prey [33]. In addition, cormorants and pelicans breed at the north end of Last Mountain Lake [19], placing breeding colonies approximately 60 km from highly developed recreational areas at the southern end of the lake.…”

Section: Discussionmentioning

confidence: 99%

Lake Use by Three Avian Piscivores and Humans: Implications for Angler Perception and Conservation

Somers¹,

Heisler²,

Doucette³

et al. 2015

TOOENIJ

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Humans and colonial piscivorous birds are often perceived to be in conflict over shared aquatic habitats and fisheries resources in inland lakes. We examined angler perception of birds and the relative abundance of American white pelicans (Pelecanus erythrorhynchos), double-crested cormorants (Phalacrocorax auritus), western grebes (Aechmophorus occidentalis), and boats on two lakes in Saskatchewan, Canada. Anglers perceived cormorants to be the biggest threat to fisheries (60%), compared to pelicans (47%), and western grebes (34%). The density of these birds and boats varied significantly between sections of the two study lakes. Boat density was higher in developed sections with shoreline communities (range 0-7/km 2 ) compared to those surrounded by agricultural land or native prairie (0-1/km 2 ). In contrast, cormorant and pelican densities were highest in areas with an undeveloped shoreline (0-22/km 2 ), and were reduced to near zero in developed sections. Western grebes did not follow the same pattern as the other two species; grebe density was generally more uniform within lakes (0-23/km 2 in all sections). Boat density was a negative predictor of pelican and cormorant density on one lake, but was a positive predictor for grebes on both lakes. Our results indicate that pelicans and cormorants avoid sections of lakes that have higher levels of human development, potentially altering the location of their foraging sites on the scale of kilometres. In contrast, western grebes were abundant in all areas of the two lakes and did not appear to avoid human development or activity. We conclude that angler perceptions are not congruent with levels of habitat use overlap with birds. In addition, western grebe responses to human activities appear counterintuitive, making interpretations difficult in a conservation context; further study is required.

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Section: Discussionmentioning

confidence: 99%

Lake Use by Three Avian Piscivores and Humans: Implications for Angler Perception and Conservation

Somers¹,

Heisler²,

Doucette³

et al. 2015

TOOENIJ

Self Cite

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show abstract

“…However, we also found a substantial number of pelicans in off shore pelagic areas, particularly in large foraging flocks (> 100 birds). Previous studies [13,16] have identified littoral zones and shallow bays as critical foraging habitats for pelicans, although deeper water sites were also used, as observed in our study. Pelicans have also been observed co-foraging in deeper water with Double Crested Cormorants (Phalacrocorax auritus), and it has been proposed that they might benefit from cormorants flushing prey towards the surface, allowing pelicans to sometimes forage successfully in pelagic zones [17].…”

Section: Habitat Characteristicsmentioning

confidence: 66%

American White Pelicans and Recreational Boaters on Lakes of the North American Great Plains: Habitat Use Overlap

Gaudet¹,

Somers²

2014

TOOENIJ

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Shoreline development and boating on lakes of the northern Great Plains of North America have increased due to recent economic prosperity. Few studies have examined the general characteristics of habitats used by foraging waterbirds and boats to determine levels of overlap. To address this issue, we conducted point count surveys of American White Pelicans (Pelecanus erythrorhynchos) and boats on two important recreational lakes in southern Saskatchewan, Canada. The majority of pelicans and boats detected used near-shore areas of the lakes, identifying the importance of shallow water habitats and providing evidence of significant overlap. The location of pelicans relative to the shore did not change in the presence of boats, and there was no significant relationship between boat numbers and pelican numbers. These analyses suggest that pelicans did not make major changes to their habitat use on the lakes as a result of boating activity. When pelicans and boats were present simultaneously at point count locations, pelicans appeared to avoid boats on one lake, but showed no detectable avoidance behavior on the other lake. The importance of interactions between recreational boating and foraging pelicans is currently unclear. Set-back distances to protect foraging pelicans from boating activity do not appear necessary based on our analyses.

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Size and Composition of Foraging Flights in Two Species of Piscivorous Colonial Birds: Limited Evidence for Intra- or Interspecific Information Transfer

Cited by 2 publications

References 36 publications

Lake Use by Three Avian Piscivores and Humans: Implications for Angler Perception and Conservation

Lake Use by Three Avian Piscivores and Humans: Implications for Angler Perception and Conservation

American White Pelicans and Recreational Boaters on Lakes of the North American Great Plains: Habitat Use Overlap

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