Consistency in long-distance bird migration: contrasting patterns in time and space for two raptors

Vardanis, Y., Nilsson, J.-Å., Klaassen, R. H. G., Strandberg, R. & Alerstam, T. (2016). Consistency in long-distance bird migration: contrasting patterns in time and space for two raptors. Animal Behaviour 113: 177–187. doi: 10.1016/j.anbehav.2015.12.014
PDF in ResearGate.net

Abstract :

As the evolutionary responses to environmental change depend on selection acting on individual differences, disentangling within- and between-individual variation becomes imperative. In animal migration research, multiyear tracks are thus needed to estimate the individual consistency of phenotypic traits. Avian telemetry studies have recently provided the first evidence of individuality across space and time in animal migration. Here, we compare repeatability patterns of routes and timing between two migratory birds, the marsh harrier, Circus aeruginosus, and the osprey, Pandion haliaetus, as recorded by satellite tracking. We found interspecific contrasts with low repeatability in timing and duration and a high repeatability in routes for ospreys, but the reverse pattern for marsh harriers. This was mainly caused by (1) larger between-individual variation in routes for ospreys (broad-front migration) than for marsh harriers (corridor migration) and a higher degree of repeated use of the same stopover sites among ospreys, and (2) higher within-individual consistency of timing and duration among marsh harriers, while individual ospreys were more flexible. Our findings suggest that individuality in space and time is not a shared trait complex among migrants, but may show adaptive variation depending on the species’ life history and ecology.

Voir aussi:

Trierweiler, C., Klaassen, R. H. G., Drent, R. H., Exo, K.-M., Komdeur, J., Bairlein, F., & Koks, B. J. (2014). Migratory connectivity and population-specific migration routes in a long-distance migratory bird. Proc. R. Soc. B 281: 20132897.

Maps showing the routes of eight adult ospreys (first row) and six adult marsh harriers (second row) that completed at least one round trip between the breeding grounds in Sweden and the wintering quarters in West Africa during 1996–2012

Maps showing the routes of eight adult ospreys (first row) and six adult marsh harriers (second row) that completed at least one round trip between the breeding grounds in Sweden and the wintering quarters in West Africa during 1996–2012. Each panel highlights the three individuals with most repeated journeys of each species (a: OM1; b: OM2; c: OF1, d: MHM1; e: MHF1, f: MHF2; see Table 1 for details) in blue (autumn) and red (spring), as well as the trips of all other individuals of the species in grey

The vulnerable Osprey population of the Al Hoceima National Park, Morocco: present status and threats

Monti, F., Nibani, H., Dominici, J.M., Idrissi, H.R., Thévenet, M., Beaubrun, P.C. & Duriez, O. (2013). The vulnerable Osprey breeding population of the Al Hoceima National Park, Morocco: present status and threats. Ostrich 84(3): 199–204.
doi: 10.2989/00306525.2013.865280

Abstract:

In the Mediterranean, most areas belonging to the initial distribution range of the Osprey Pandion haliaetus have been lost and local populations have disappeared in recent decades because of persecution. Even though direct management actions have allowed local partial recovery, the Mediterranean population currently only holds a few tens of breeding pairs and is still exposed to local extinction risks. One of the last Mediterranean Osprey breeding areas lies along the North African coast between Morocco and Algeria. In this paper, we report new information on the Osprey population within the Al Hoceima National Park, Morocco. The status of the population for 2012 and 2013 is reported and compared with data collected during the period 1983–1990. A reduction in number of nests and breeding pairs was observed and a 35.7% decrease in the population size recorded. In addition, we discuss the main identified threats to Osprey habitats (e.g. dynamite and poison fishing) that affect the Osprey breeding population in this area. In this context, we stress the necessity for urgent measures to be adopted at the local scale for the protection of this vulnerable population in the light of a sound conservation strategy also at the scale of the Mediterranean.

Osprey (Pandion haliaetus) at Al Hoceima National Park, Morocco

Osprey (Pandion haliaetus) at Al Hoceima National Park, Morocco (photo: A. El Idrissi Essougrati).

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