Hormones and reproductive effort in arctic seabirds.

In the frame work of the ORNITHO-ENDOCRINO research program, we propose a project where the aim is to study the effects of persistent organic pollutants and heavy metals on the endocrine stress response of the Black-legged kittiwake in Svalbard, where pollution by contaminants is an important issue. We will investigate the influence of contaminants burden by using an acute stress protocol. We will use non destructive sampling methods and search for organic compounds (DDT, DDD, DDE, HCB, PCBs, and PBDEs) and heavy metals known to be toxic. Using miniature GLS loggers we will document how migratory strategies and winter distribution affect the uptake of pollutants. We will also study the fitness (survival, reproduction) consequences of the stress response/contaminants interactions.

In 2012

Renewal for 4 years 1/4

Data collection by 2 CEBC researchers and one PhD student. Sample analysis for hormones and contaminants will be achieved at CEBC, LIENS (in France), and by NILU (Norway) .
Objectives and hypothesis for the 2012 sesaon:
1) Assess the effects of persistent organic pollutants ((PCBs, p,p’ DDE, HCB and oxychlordane as well as emerging persistent organic pollutants such as brominated flame retardants (BFRs) and perfluorinated compounds (PFCs)) and heavy metals (mercury and cadmium) on the stress axis of kittiwakes (Rissa tridactyla) in the Kongsfjord, Svalbard. We will test the hypothesis that highly contaminated individuals bear elevated corticosterone levels and low prolactin levels and to show an impaired hormonal response to stress. During the parental phase (mid June-mid July) blood samples will be collected (1 ml on N=50 males and N=50 females) to determine baseline and stress-induced corticosterone and prolactine levels as well as contaminants burden (POPs and heavy metals). We will then observe individually marked birds to assess clutch size and reproductive success (number of surviving chicks).
2) Document how migratory strategies and winter distribution recorded via miniature 1.5 g, geolocation sensors (GLS) affect stress levels and the uptake of pollutants. We will compare stress hormones POP and heavy metals levels measured in feathers among birds from the same breeding population who migrate to different wintering areas. During the 2012 season we will fit 30 birds (15 males and 15 females) with miniaturized GLS (Global Location Sensing Loggers, 1.5 g), manufactured by British Antarctic Survey (collaboration with Dr. R. Phillips) to identify wintering areas. These miniaturized light-level geolocators measure light intensity, sea water immersion and sea temperature. Longitude and latitude are calculated from timing of sunrise and sunset, and activity and energetic cost can be estimated from the latter measurements. Devices will be deployed during 1 year and will be taken back next year, when birds will return from their wintering areas. When captured, blood and feather samples will be taken to determine hormones and contaminants content.
Blood sampling and acute stress protocol
Kittiwakes will be captured at their nest with a noose on the end of a 5 m fishing rod, a non harmful technique. We will use non destructive sampling (approximately 1 ml blood sample). Baseline corticosterone and prolactin levels will be obtained by taking blood samples immediately after capture (within 3 min) to avoid handling influences on these stress hormones. Blood samples (1 ml) will be obtained by puncture of the brachial vein, a method widely used for birds and well mastered by the applicants. Stress response will be measured by using a standardized capture/handling stress protocol: after the completion of the blood sampling, birds will be placed into individual bags for 30 min (in vertebrates maximum corticosterone levels are reached within 30 min). After 30 min of restraint, a second blood (200 μl) sample will be taken to determine acute stress levels. The bird will be then released and kittiwakes resume normal activities in a few minutes after sampling. Baseline blood sample will be partly used for pollutant burden assay. The remaining blood will be centrifuged and plasma will be decanted and stored at –20°C until assay.

In 2011

Year 4/4

The aim of the ORNITHO-ENDOCRINO project is to study the influence of environmental stress on the breeding phenology of Kittiwakes (Rissa tridactyla) in Svalbard. Our previous investigations suggest a very important role of the male in provisioning the female and thus in influencing the stress levels, body reserves and laying of their mates. In 2011, we want to experimentally reduce the male provisioning effort, by increasing the male’s foraging costs (transitory handicap by clipping the wing feathers, N=15 males). If our hypothesis is right we should observe handicapped males to increase their time at sea and to reduce their provisioning effort to the females. These females are thus expected to bear elevated corticosterone (stress hormone) levels and to delay the egg-laying date. In 2011 we will also study the foraging areas used by pre-laying kittiwakes (N=30) by means of miniaturized GPS. Tracks will be analysed in relation to oceanographic parameters to know which type of pre-laying foraging area is used. This will allow us to estimate the relative degree of behavioural flexibility of kittiwakes in relation to foraging conditions in a given year and help us interpreting the variations in pre-laying hormone levels. In 2011, we will recapture birds fitted in 2010 with miniaturized GLS (Global Location Sensing Loggers) to identify marine sectors used during winter 2010-2011. In 2011, we will deploy 20 new GLS.

In 2010

Year 3/4

We want to continue to explore the functional role of corticosterone (the stress hormone) on the timing of breeding. In 2009, we successfully advanced timing of egg-laying by means of low dose hormone implants. In 2010, we will increase corticosterone levels by means of high dose subcutaneous implants in N=12 females. If our working hypothesis is right, we should observe a delayed egg-laying in those females. In 2010 we will also study the foraging areas used by pre-laying kittiwakes (N=30) by means of miniaturized GPS. Tracks will be analysed in relation to oceanographic parameters and to know which type of pre-laying foraging area is used. This will allow us to estimate the relative degree of behavioural flexibility of kittiwakes in relation to foraging conditions in a given year and help us interpreting the variations in pre-laying hormone levels. We will recapture birds fitted with miniaturized GLS (Global Location Sensing Loggers) to identify marine sectors used during winter 2009. In 2010, we will deploy 10 new GLS.

During the 2009 season

Year 2/4

We want to identify feeding areas used by kittiwakes (N=30) during the prenuptial period, through the installation of miniaturized GPS. The data will be analyzed in relation to oceanographic parameters available and will determine whether, in 2009, the birds are exploiting anew the ocean and coastal areas identified in 2008. Ten birds will also be equipped with GLS (Global Location Sensing Loggers) miniaturized to identify marine areas used during winter and early spring.

During the 2008 season

Year 1/4

We want to describe the levels of hormones of the hypothalamic-gonado-pituitary axis and check if there is a correlation between natural levels of corticosterone during the prenuptial phasis and individual laying date (N = 70 birds).