Verónica Rodrigues Costa Neves
Unraveling factors affecting individual quality and ensuring population viability of two species of sympatric storm­petrels
Area of RIS3: Pescas e Mar
Institution Center: Centro Okeanos
State: ongoing

The results from this project will be of importance to fill a gap of knowledge concerning the ecology of the vulnerable and Azores­endemic Monteiro’s storm­petrel, but also of the Band­rumped storm­ petrel. The results of this post­doc project will also contribute to establish marine protected areas and to assess the good environmental status of the marine ecosystem.

The project will study in detail the following aspects:

  1.  Identifying and characterizing the location and stability of foraging hotspots of Monteiro’s and band­rumped storm­petrels, as well as their migration strategies and wintering areas
    Successfully identifying marine areas that are appropriate for the protection of seabird populations implies a deep understanding of the spatial distribution of seabirds at sea. When breeding, seabirds forage in areas whose exploitation is constrained by several factors, such as prey availability and maximum foraging ranges. Outside the breeding season the scenario changes and birds normally cover great distances and use distinctive areas for stopovers. The foraging areas along migratory routes are also very important for the conservation of seabirds. Determining the spatial distribution of seabirds during the non­breeding period, especially as is the case for very small species such as our study birds, has so far been virtually impossible. However, the recent development of state­of –the– art GPS loggers weighing just 1g is becoming to make it possible. Over the next two years we will study the foraging and migration strategies of the two species of sympatric storm­petrels and for the first time unravel the marine areas that are crucial for the conservation of these endangered species. We will study the foraging areas during both incubation and chick­rearing and for each species we will have a sample that will enable us to investigate differences in sex, stage of the breeding cycle and year. Previous studies on similar species found no severe effects resulting from the use of loggers. Nevertheless, given the conservation importance of our study species, the impact of the loggers will be evaluated using physiological parameters (stress hormones, blood cell counts) in tracked birds and in a control group.
  2. Characterizing the breeding behaviour of Monteiro’s and band­rumped storm­petrels
    To maintain stable populations of wild animals it all comes down to ensure optimal levels of breeding success and survival. By understanding the relative importance of the factors that contribute to birds’ successful reproduction we can identify the more efficient measures to preserve bird populations. Procellariiformes are long­lived species at the top of food chains with a K­reproductive strategy. They provide good sentinel species of the Ocean ´s health but they may also be very sensitive to ecological stress (pollution, climate change, over­fishing, etc). Given the current state of ecological degradation of our planet it is fundamental to monitor and understand the fragilities and the plasticities of wild species, as well as the ways individuals adapt to change. The two sympatric populations of Azorean storm­petrels are key species given their ecologic and evolutionary peculiarities. Praia islet is the ideal study location with an amazing study colony holding 150 artificial easily accessible nests and a population that has been monitored over the last 15 years.
  3. Examining the relationships between physiological state, foraging strategy and breeding success We will investigate whether the physiological state of individuals (triglycerides, blood cell counts) is correlated with foraging effort and breeding success. We will also investigate possible differences in physiological state between sexes and between breeders, non­ breeders and nestlings. Tryglicerides have been shown to be a good indicator of nutritional state in Wilson ´s storm­petrels (Quillfeldt et al. 2004). We will study the change in triglyceride levels in adult Monteiro ´s and band­rumped storm­petrels in relation to foraging area and foraging trip duration over two consecutive breeding seasons. Additionally, we will monitor closely the tracked individuals and use physiological parameters to assess potential adverse impacts of the loggers.
  4. Caracterizing the diet of Monteiro’s and band­rumped storm­petrels, determining how it varies across the breeding cycle and between years and investigate how it relates to foraging strategy, physiological state, body condition and breeding success. Knowing where birds feed and their foraging strategy is vital for the conservation of their foraging areas but is important to study their diets, as they are also an important determinant of individuals’ body condition. Additionally, it is important to ensure that prey organisms are protected and available as necessary. Therefore, we will study the diet of both species and investigate variations between sexes, stages of the breeding cycle (incubation and chick­rearing) years.
    There are currently several methods available to study seabird diets. We will combine a range of conventional and well­established method (stomach flushing and stable isotope analysis) with a novel molecular technique, which identifies prey DNA faecal samples (Symodson, 2002, Alonso et al. 2014). The stomach flushing technique was first used in penguins in the early 1980’s (Wilson 1984) and since then it has been successfully used in a large variety of seabirds and other marine species, including turtles. The PI of this project has a vast experience in using this technique and has also successfully tested it on storm­petrels. This technique has the advantage of providing very detailed information on prey items.
    Molecular (i.e. PCR­based) methods, involving extraction and analysis of prey DNA from the digestive tract of foragers or faecal samples, have the clear advantages of being non­invasive and providing very detailed information on diet composition, potentially to the species
    level (Symondson 2002). To date, few studies using this methodology were conducted on the diets of seabirds (Deagle et al. 2007, 2010) and only one has investigated the diet of a seabird species during migration (Medeiros 2010).
  5. Plastic exposure ­ For each species, we will collect 30 samples of preen gland oil from adults (15 males and 15 females) and 15 samples from chicks following Hardesty et al. (2014). Birds will be captured by hand at their nests on Praia islet. Samples will be collected by gently squeezing the uropygial gland of birds. The oil and gland exudates will be collected using clean metal spatulas with no previous contact with plastic and a pre­cleaned cotton wool. The cotton will be wiped over the uropygial gland and then put into a pre­cleaned glass vial, sealed, labelled and stored in a refrigerator. At the lab, samples will be processed following Hardesty et al. (2014). Preen oil compounds will be determined using a Varian 3800 Gas Chromatography. Peak identification will be determined based on their retention times. We will also inspect regurgitations of sampled individuals to look for plastic items. Any plastic found will be separated from diet items, and the colour, size and shape will be recorded.
    With all the above data, we will investigate the relationships between foraging areas, physiological state, body condition, breeding behavior, breeding success and diet. We will also investigate which parameters are a better proxy of individual quality.

Fieldwork and data collection will require two years, since it will be necessary to recapture individuals equipped with GLS in the following season to study migrations and wintering areas. Additionally, it is important to collect data on two consecutive breeding seasons to investigate whether fidelity to foraging areas and breeding parameters may vary with environmental conditions.
The applicant has worked with the Azorean seabird community for almost two decades and is experienced in seabird’ tracking, diet and conservation.