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Summary: The 'a'o, or Newell's Shearwater Puffinus newelli, is an endangered shearwater species endemic to the Hawaiian Islands, with 90% of the world population found on Kaua'i. Understanding the breeding phenology of the species is vital for identifying key periods for colony management actions and the timing and exposure frequency to infrastructure threats such as powerline collisions and light attraction. We used a combination of direct burrow monitoring and remote cameras at multiple colonies between 2012 and 2019 for a detailed assessment of the breeding phenology for this species. Breeding adults started arriving at the burrow in mid-April, some (but not all) underwent a two-week exodus in May and returned at the end of May to commence incubation. Incubation continued until mid-July. The chick-rearing period ran until the end of September. Fledging peaked in October with the last birds fledging towards the middle of November. Breeding was not synchronised, with a 59-day gap between the first and last fledging birds. The importance of this information to management actions is discussed, particularly in terms of directing management actions to key periods of vulnerability to introduced predators (such as peak incubation, chick emergence, and exercising prior to fledging), the precise timing of fledgling fallout related to light attraction, and directing colony-monitoring actions and translocation projects. We also consider the utility of the data in assessing species composition of powerline collisions and collision risk. Future work using acoustic monitoring is recommended for assessing the phenology of non-breeders and prospectors at colonies. [ABSTRACT FROM AUTHOR]

The ‘Ua‘u (Hawaiian Petrel Pterodroma sandwichensis) is an endangered petrel endemic to the Hawaiian Islands. In this short paper, we describe two cases of Hawaiian Petrels with leucistic plumage recorded on the island of La¯na‘i. In both cases, the birds were chicks that fledged successfully in different years from the same burrow. There is only one other documented case of leucism recorded for this species in the Hawaiian Islands despite intensive monitoring of petrel burrows on Kaua‘i, La¯na‘i, and Maui over the last few decades, highlighting the rarity of this plumage aberration. [ABSTRACT FROM AUTHOR]

Despite being one of the most widespread seabird species in the main Hawaiian Islands, little is known about the breeding phenology of the White-tailed Tropicbird Phaethon lepturus dorotheae. This is presumably due to its low conservation concern, coupled with the inaccessibility of most of its nesting sites, meaning that there are an extremely limited number of known nest sites where birds could be monitored directly. To better understand the breeding phenology of this species on Kaua'i, we reviewed data from the Save Our Shearwaters (SOS) program (a Kaua'i-based seabird rescue and rehabilitation program) to analyze when fledgling tropicbirds were recovered. We discovered 313 records of hatch-year birds in the database. Using breeding data from other populations of this species and back-dating the phenology based on these fledging records from the SOS database, we conclude that this species breeds year-round on Kaua'i. However, typically, eggs are laid between March and September (with a peak in June). Chicks hatch between April and October (with a peak in July) and birds fledge between July and January (with a peak in October). The number of tropicbird fledglings handed over to SOS has increased significantly since the program's inception in 1979, to a high of 31 fledglings received in 2016. It is not clear whether this indicates an increase in the population of this species on Kaua'i, an increase in public awareness of seabird conservation on the island, or both. Data from rescue and rehabilitation projects can be an important data resource for studying rare, cryptic, or difficult-to-access seabird species. [ABSTRACT FROM AUTHOR]

The Barn Owl Tyto alba was introduced to the Hawaiian Islands in the late 1950s as a biological control for rats Rattus spp. and has since become common throughout the main Hawaiian Islands. Herein, we address the impact on Hawaiian seabirds by summarizing the number of seabird depredations recorded in the database of the Kaua'i Endangered Seabird Recovery Project. Data were collected on Kaua'i and the neighboring islets of Lehua and Moku'ae'ae between January 2011 and October 2018 as part of ongoing seabird survey work; 379 Barn Owl depredations were recorded of eight seabird species, the most common of which were Wedge-tailed Shearwater Ardenna pacifica, Black Noddy Anous minutus, and Bulwer's Petrel Bulweria bulwerii. Included were 21 depredations on federally listed Newell's Shearwater Puffinus newelli and Hawaiian Petrel Pterodroma sandwichensis. Most depredations were on adult birds. The effectiveness of Barn Owl control was also evident, with depredations on Lehua Islet decreasing significantly after dedicated control operations were initiated. Barn Owl control should be considered as an integral part of all Hawaiian seabird management programs. [ABSTRACT FROM AUTHOR]

The Band-rumped Storm-petrel (BRSP) Oceanodroma castro has a large breeding range, spanning the warmer portions of both the Atlantic and Pacific Oceans. The Hawaiian population is one of the most cryptic and under-studied seabird species in the archipelago, and its breeding phenology and distribution are poorly known. We used several methods, including human auditory surveys, automated acoustic surveys, mist-netting, and data from a seabird rescue and rehabilitation program to assess the breeding phenology and distribution of BRSP on the island of Kaua'i and adjacent Lehua Islet. Our data show that the species arrives at breeding colonies on Kaua'i in late May, with birds fledging from late September to mid-November. Unlike BRSP breeding populations in the Galápagos, Azores, and Madeira, a winter breeding population was not apparent. Breeding colonies were found to be concentrated along the Na Pali coast, particularly within canyons from the Kalalau Valley to Polihale, as well as the Waimea Canyon. These areas are characterized by sparsely vegetated, very steep cliffs. Small pockets of BRSPs were also encountered in some of the wetter and heavily vegetated valleys associated with exposed rocky cliff faces. A large concentration of storm-petrel activity was also recorded on the southeastern slopes of Lehua Islet. A model created to predict Kaua'iwide distribution indicated that the key predictive variables, found in 85% of all models, were average rainfall, EVI (Enhanced Vegetation Index to assess broad vegetation types), and slope. Identifying this species' breeding phenology, range, and habitat requirements is a key step to inform conservation efforts for BRSPs elsewhere in the archipelago. In that regard, much work remains to be done. [ABSTRACT FROM AUTHOR]

Moku'ae'ae Rock Islet is located off the north shore of Kaua'i and is protected as a Hawai'i State Seabird Sanctuary. In the late 1970s it was also the site of a cross-fostering project for the endangered Newell's Shearwater, Puffinus newelli. Few avifauna surveys have been undertaken on the islet, and none since 2007. In 2013 and 2015, we conducted burrow searches across the entire islet to obtain breeding population estimates for each species and to evaluate whether the Newell's Shearwater had become established as a breeding species after the cross-fostering project. Auditory surveys were also conducted for 2 hr after sunset and 1.5 hr before sunrise, which are the peak calling periods for the Newell's Shearwater on Kaua'i. A total of seven seabird species was recorded on the islet, of which three, Bulwer's Petrel, Bulweria bulwerii; Wedge-tailed Shearwater, Ardenna pacifica; and Red-tailed Tropicbird, Phaethon rubricauda, were confirmed breeding. This is the first time Bulwer's Petrel has been confirmed breeding on Moku'ae'ae. Searches for Newell's Shearwater did not produce evidence that this species breeds on the islet, suggesting that the cross-fostering project was not successful. Although the islet is small, it represents an important refuge for seabird species. However, high levels of depredation were recorded on Bulwer's Petrel; we conclude that these were all killed by the introduced Barn Owl, Tyto alba, based on disposition of the bodies and the injuries they had sustained. Management recommendations for the islet include creation of a management plan, annual breeding bird surveys, annual rat monitoring, and Barn Owl control. [ABSTRACT FROM AUTHOR]

Illegal hunting is a widespread problem in the Maltese Islands. As well as having a significant impact on the islands' breeding birds, the illegal hunting of migratory birds has a wider, international dimension. To investigate the international impact of illegal hunting in Malta we considered the entire ring recovery database of the Valletta Bird Ringing Scheme, from the 1920s to the present. All records of birds that were ringed overseas and shot by hunters in Malta were analysed, comprising a total of 435 records of 84 species from 36 countries. The majority of these ring recoveries (91.7%) were from species listed as protected and non-huntable throughout the European Union, with a significant proportion listed as European Species of Conservation Concern. Birds of prey were particularly represented in the database, 78.6% of which were ringed as nestlings or juveniles, highlighting the impact of illegal hunting on this group of species in particular. Species targeted illegally by Maltese hunters originate from countries throughout Europe and Africa, particularly Finland, Sweden, Tunisia, Italy and Germany. For rare species or those with small breeding populations in affected countries, illegal hunting could therefore have a significant impact on the long-term persistence of European populations. Poaching of species such as the pallid harrier Circus macrourus and saker falcon Falco cherrug could have a global impact on their populations. [ABSTRACT FROM PUBLISHER]