Abstract: Avian chemosignaling remains relatively unexplored, but its potential importance in birds social behaviors is becoming recognized. Procellariiform seabirds provide particularly appropriate models for investigating these topics as they possess a well-developed olfactory system and unequalled associated capabilities. We present here results from a detailed chemical examination of the uropygial secretions (the main source of avian exogenous chemicals) from 2 petrel species, Antarctic prions and blue petrels. Using gas chromatographymass spectrometry techniques and recently developed multivariate tools, we demonstrate that the secretions contain critical socioecological information such as species, gender, and individual identity. Importantly, these chemosignals correlate with some of the birds olfactory behaviors demonstrated in the field. The molecules found to be associated with social information were essentially large unsaturated compounds, suggesting that these may be precursors of, or correlates to the actual airborne signals. Although the species-specific chemosignal may be involved in interspecific competition at the breeding grounds, the role of the sexually specific chemosignal remains unclear. The existence of individually specific signals (i.e., chemical signatures) in these birds has important implications for processes such as individual recognition and genetically based mate choice already suspected for this group. Our results open promising avenues of research for the study of avian chemical communication.

Abstract: Geographic variation in animal vocalisations, ranging from micro- to macro-variations, has now been widely documented. These dialects can impair communication between separated groups or populations and thus may play a role in speciation processes. Although the existence of geographical variation has been already shown in some pinnipeds species, the extent to which individuals perceive it is poorly understood. Here, we studied this question in the bearded seal Erignatus barbatus, a species found across different arctic regions. As in other phocids, bearded seal males emit sophisticated acoustic displays while defending an aquatic territory during the breeding season. First, we used playbacks to demonstrate that the trill has a function in territorial defence. Second, we used synthetic trills from two distinct populations (Nunavut and Greenland), to show that bearded seal males perceived the geographic variation in the trills. Males from Greenland responded more strongly to trills from local males than those from a distant area (Nunavut). This study provides the first experimental evidence that phocid males can perceive geographic variation in their vocalisations. Acoustic analyses combined with playback experiments can help to identify distinct populations in bearded seals. This may then provide information on both strength and scale of breeding site fidelity in this and potentially other species.

Abstract: The main purpose of this paper deals with the orientation estimation
problem of a rigid-body motion in space. We present an algorithm for attitude
estimation, expressed in quaternion representation, using low-cost sensors as
3-axis accelerometer, 3-axis magnetometer and 3-axis gyroscope. The
algorithm is based on a complementary nonlinear observer coupled with a
Levenberg Marquardt Algorithm (LMA). Moreover, the proposed solution
exploits kinematic equation model and includes the estimation of rate gyros
biases to compensate angular velocity measurements. This algorithm is
developed in order to address the well-known problem of the weak dynamics of
the attitude sensors (accelerometer and magnetometer). The efficiency of the
proposed observer is illustrated by an attitude estimation example in presence
of realistic measurements provided by low-cost sensors. Some preliminary
experimental results are provided also to prove the performance of the
proposed method. The developed approach will be applied in future works in
Bio-logging area which interests to study the animal behavior and its energy
expenditure by determining its movement patterns (3D motion or orientation).