Cristina Perry Nava (Departamento de Oceanografia e Pescas, Centro do IMAR da Universidade dos Açores, Horta, Faial, Azores, Portugal) and colleagues have published in the Journal of Ornithology on assortative mating in Cory’s Shearwater Calonectris borealis.

The paper’s abstract follows:

“Many bird species rely on visual cues for mate choice, including those provided by body /size or by the size of a body appendage.  Mate choice based on size may lead to size-assortative mating, which may in turn have consequences for reproductive performance.  In this study, we examined whether body size influences mate choice decisions of Cory’s Shearwater Calonectris borealis, a seabird with nocturnal activity on land.  We found evidence of negative assortative mating for bill morphology (nostril height and bill length), but found no assortative mating according to body mass, tarsus length, and wing length.  In addition, we investigated the influence of negative assortative mating and individual body size-related traits on reproductive performance, i.e., laying date and breeding success.  We found that laying date and breeding success were not correlated with the extent of assortative mating, i.e., the assortatively mating breeders did not lay earlier and were not more likely to breed successfully.  However, we found that heavier females (body mass measured during pre-laying) laid later in the season.  We discuss these results in the light of possible effects of acoustic signals and foraging strategies on the mating pattern.  Furthermore, we suggest that some female attributes may be crucial for breeding success in Cory’s Shearwaters.”

 
Cory's Shearwater, photograph by Paulo Catry

Reference:

Nava, C.P.,  Kim, S.-Y., Carvalho Magalhães, M. & Neves, V. 2014.  Do Cory’s Shearwaters Calonectris borealischoose mates based on size?  Journal of Ornithology  DOI 10.1007/s10336-014-1070-8.

John Cooper, ACAP Information Officer, 28 May 2014

Jémérie Demay (Centre d'Études Biologiques de Chizé, Villiers-en-Bois, France) and colleagues report in the journal Antarctic Science on the Northern Giant Petrel Macronectes halli breeding for the first time on Amsterdam Island in the southern Indian Ocean.  A single pair hatched its egg, with the chick having disappeared by 21 December 2013.  It is considered the breeding attempt failed.  Breeding was not observed at the same locality the following season, although displaying birds were present. Amsterdam now becomes the most northerly known breeding site for the species.

 Northern Giant Petrel, photograph by David Boyle

Reference:

Demay, J., Thiebot, J.-B., Delord, K. & Barbraud, C. 2014.  First breeding record of the Northern Giant Petrel Macronectes halli at Amsterdam Island. Antarctic Science doi.org/10.1017/S0954102014000182 

John COoper, ACAP Information Officer, 27 May 2014

A joint endeavour between tourists and the United Kingdom aims to survey Wandering Albatrosses Diomedea exulans at South Georgia (Islas Georgias del Sur)* in January next year.

Cheesemans’ Ecology Safaris, a USA company, plans to take a group of seven tourists and an expedition leader south on the 26-m Hans Hansson to help support a decadal count of breeding pairs of the island’s Wandering Albatross population.  Information from the albatross survey, to be led by island veteran Sally Poncet, will be made available to ACAP.  The ship will carry up to four scientists who will undertake the actual counts.

Wanderers display on a South Atlantic island, photograph by Richard Phillips

 According to the tourist company’s website participants will have the opportunity to join the scientists ashore to assist with the survey or explore with professional photographer Scott Davis.  Some of these visits will be to localities not normally open to tourism - such as Albatross Island in the Bay of Isles and regions along the main island’s south-western coast under special permit (click here).  The expedition is set to last for nearly four weeks and intends to circumnavigate the main island.

Populations of Wandering Albatrosses in the South Atlantic have been decreasing over recent years leading to ACAP identifying them as being a high priority for conservation action at its Fourth Session of the Meeting of the Parties held in Lima, Peru in April 2012 (click here).  Data from the planned survey should provide an indication of the island’s current population trend and address the requirements of article 4.1 of the ACAP Action Plan, providing essential information to aid in the species’ conservation.

John Cooper, ACAP Information Officer, 13 May 2014, updated 26 May 2014

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.

The invasive plant Golden Crownbeard Verbesina encelioides, which forms “cornstalk-high stands”, is being removed from several atolls in the USA’s Northwestern Hawaiian Islands (NWHI), leading to improved breeding habitat for ACAP-listed Black-footed Phoebastria nigripes and Laysan P. immutabilis Albatrosses.  The plant is a fast-growing and prolific annual that thrives in the Hawaiian climate.

Golden Crownbeard Verbesina encelioides

The U.S. Fish and Wildlife Service reports that more seabirds, including albatrosses, attempt breeding and more chicks survive among native grass species than within non-native Verbesina stands on Midway Atoll National Wildlife Refuge, part of the Wold-Heritage-listed Papahanaumokuakea Marine National Monument (click here).  Laysan and Black-footed Albatrosses bred at near-record levels in 2012/13 on Midway, although “biologists will need three or more years to know if the rise is due to Verbesina control.”

Verbesina is thought to have been introduced to Midway in the 1930s.  “By the late 1990s, when eradication efforts began, the plant covered most of Midway’s three islands, reducing seabird nesting density, reproductive success, albatross chick survival and biodiversity.  Verbesina grows rapidly each year, forming thick stands that reduce albatross nesting and limit air flow to chicks in their nests, putting them at risk of death from dehydration.”

“For the past two years, crews have hand-sprayed Verbesina almost daily with herbicides; year-round seabird nesting precludes the use of tractors or heavy equipment.  Spraying has knocked out most mature Verbesina plants on Midway’s Eastern Island.  If all goes well, emergent seedlings will be gone by early 2017 on Eastern and Spit islands and by early 2018 on bigger Sand Island.  Native grasses and other native plants are being replanted to restore seabird nesting habitat, secure coral sand and build coastal dunes to protect against waves.”

Black-footed and Laysan Albatrosses breeding on Midway Atoll

To guard against re-infestation or invasion, the Refuge imposes strict quarantine procedures.  Personnel travelling to Eastern Island must pass through shoe-cleaning stations at the boat pier.  All equipment is cleaned before transport from Honolulu to Midway and before use on Eastern Island.  Travellers from Honolulu to Midway must also clean their shoes and gear before flights and voyages.  Only new clothing and thoroughly cleaned equipment are allowed at the other atolls and islands within the Papahanaumokuakea Marine National Monument.

Verbesina eradication is being undertaken with a US$1 million National Wildlife Refuge System grant and matching funds from the National Fish and Wildlife Foundation.

Read an earlier item on Verbesina control in ACAP Latest News here.  Verbesina control and native plantings are also underway on Kure Atoll in the NWHI in order to improve breeding habitat for albatrosses and other seabirds (click here).

John Cooper, ACAP Information Officer, 26 May 2014