Can Supplemental Foraging Perches Enhance Habitat for Endangered San Clemente Loggerhead Shrikes?

Lynn, Suellen; Martin, John A.; Garcelon, David K.

doi:10.1676/05-055.1

Cited by 4 publications

(2 citation statements)

References 15 publications

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“…Supplemental food is provided to juvenile shrikes for at least 1 week post-release and is gradually decreased as shrikes disperse from the release site (Nichols et al, 2010). Released captive-reared eastern loggerhead shrikes have low foraging success (16%; Imlay & Andrews, 2008) compared to that observed in wild and captive-reared San Clemente loggerhead shrikes Lanius ludovicianus mearnsi (Lynn et al, 2006). It is possible that older release birds are more dependent on 3 Breeding success of captive-wild and wild-wild shrike pairs in Carden, Ontario, during 2005-2011, with mean no.…”

Section: Discussionmentioning

confidence: 99%

Recruitment of juvenile, captive-reared eastern loggerhead shrikes Lanius ludovicianus migrans into the wild population in Canada

Lagios¹,

Robbins²,

Lapierre³

et al. 2014

Oryx

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High post-release survival, low dispersal and the recruitment of captive-reared individuals into the wild population are critical to the success of any reintroduction programme. Reintroducing a migratory species poses an additional challenge as success also depends on the return of captive-reared individuals to breeding grounds in subsequent years. We investigated the effects of seven husbandry and management factors on the return rate of captive-reared eastern loggerhead shrikes Lanius ludovicianus migrans and documented the recruitment of returning individuals. During 2004–2010, 564 juveniles were released in Ontario, Canada, as part of a field propagation and release programme and there were 27 confirmed sightings of returning birds during 2005–2011. Returning birds were significantly more likely to have been released in large groups of juveniles (9–10 birds) at 5.5 weeks post-fledging from the Carden field propagation site. Comparisons of the number of young fledged and survival to 2 weeks post-fledging revealed similar results for pairs comprising one captive-reared and one wild-reared individual and pairs comprising two wild individuals. These results highlight the contribution of captive-reared shrikes to the recovery of the wild population and the importance of monitoring outcomes and evaluating techniques.

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Section: Discussionmentioning

confidence: 99%

Recruitment of juvenile, captive-reared eastern loggerhead shrikes Lanius ludovicianus migrans into the wild population in Canada

Lagios¹,

Robbins²,

Lapierre³

et al. 2014

Oryx

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“…Although agricultural land, including rangeland, can have high abundances of raptor prey species (including species that farmers consider pests), in many areas raptor use of these fields for foraging is limited by a lack of suitable perch and nesting sites (Preston 1990, Widen 1994. By providing artificial perches for raptors, farmers can attract more birds of prey to their land (Hall et al 1981, Kay et al 1994, Kim et al 2003, Lynn et al 2006, Witmer et al 2008, Omeg 2012) and may benefit from increased predation pressure raptors have on vertebrate pests such as rodents (Kay et al 1994).…”

Section: Introductionmentioning

confidence: 99%

Raptor Use of Artificial Perches in California Rangelands in Fall

Kross¹,

Chapman²,

Craig³

et al. 2018

vertebrate_pest_conference

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Most raptor species rely on perches for hunting, resting, preening and roosting and in many agricultural areas the availability of adequate perches can limit raptor abundance and diversity. This has negative implications for both raptor conservation and the natural pest control services they can provide for farmers. Installing artificial perches on agricultural lands can therefore benefit both raptors and farmers. However, installing perches under current guidelines is difficult on California's 38 million acres of rangelands, where rocky soil can be restrictive to anchoring poles belowground. We developed a novel method for modifying existing fenceposts to support raptor perches. These raptor perches are relatively light, easy to construct, can be transported in multiple pieces and assembled in the field. We installed 16 artificial raptor perches in four representative habitats on a California ranch to 1) determine if raptors will use artificial perches in each habitat; 2) test raptor preferences for different perch configurations; and 3) observe which raptor species utilize perches. Here, we share our perch design as well as our results from monitoring perches between August and November 2017. We found that American kestrels, great horned owls, barn owls, and red-tailed hawks utilized perches, as did a number of non-raptor species. Perch use by raptors was highest in an irrigated pasture and at a mid-elevation grassland site located on a hill. Perches at a low-elevation, unirrigated pasture with no slope and perches located in higher elevation oak woodland sites were used significantly less. In all habitats raptors preferred to utilize 15-foot perches over 20-foot perches. Raptors rarely utilized a lower perch when two were available on a single pole, suggesting that this added feature is not necessary to attract the species we observed.

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Population size of Island loggerhead shrikes on Santa Rosa and Santa Cruz Islands

Stanley

Teel

Hall

et al. 2012

Wildlife Society Bulletin

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Island loggerhead shrikes (Lanius ludovicianus anthonyi) are an endemic, genetically distinct subspecies of loggerhead shrike on California's Santa Rosa, Santa Cruz, and Santa Catalina Islands (USA). This subspecies is listed as a Species of Special Concern by the California Department of Fish and Game and has been petitioned for federal listing under the Endangered Species Act. The combination of suspected low numbers and the possibility of federal listing, prompted us to undertake a study to rigorously estimate the number of remaining individuals on Santa Rosa and Santa Cruz Islands. During the 2009 and 2010 breeding seasons, we surveyed sample units on Santa Rosa and Santa Cruz Islands using a double‐observer method with independent observers to estimate joint detection probabilities (p), where we selected units under a stratified random sampling design. We estimated shrike abundance to be 169 in 2009 (p = 0.476) and 240 in 2010 (p = 0.825) for Santa Rosa Island, and 35 in 2009 (p = 0.816) and 42 in 2010 (p = 0.710) for Santa Cruz Island. These numbers, especially for Santa Rosa Island, are higher than previously reported but nevertheless are still low. Rapid vegetation change on both islands due to recent removal of nonnative herbivores may threaten the habitat and status of this subspecies and, therefore, we suggest that intensive demographic and habitat use research be initiated immediately to obtain additional information vital for the management of this subspecies. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

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Can Supplemental Foraging Perches Enhance Habitat for Endangered San Clemente Loggerhead Shrikes?

Cited by 4 publications

References 15 publications

Recruitment of juvenile, captive-reared eastern loggerhead shrikes Lanius ludovicianus migrans into the wild population in Canada

Recruitment of juvenile, captive-reared eastern loggerhead shrikes Lanius ludovicianus migrans into the wild population in Canada

Raptor Use of Artificial Perches in California Rangelands in Fall

Population size of Island loggerhead shrikes on Santa Rosa and Santa Cruz Islands

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