Migration route, stopping sites, and non-breeding destinations of adult Black-tailed Godwits breeding in southwest Fryslân, The Netherlands

Abstract

In this paper, we extend our understanding of the migration of Black-tailed Godwits (Limosa limosa limosa) by describing: (1) the orientation and geographic locations of individual migratory routes and (2) the spatial distribution of godwits across seasons and years. We accomplish this using satellite-tracking data from 36 adult godwits breeding in the 200-ha Haanmeer polder in The Netherlands, from 2015 to 2018. During both southward and northward migration, godwits used a narrow migratory corridor along which most individuals made stops within a network of sites, especially the Bay of Biscay, France and Doñana, Spain. Most sites were used consistently by the same individuals across years. However, sites in Morocco were used during northward migration by 75% of individuals, but not revisited by the same individual across years. After southward migration, a small proportion (15%) of godwits spent the entire non-breeding period north of the Sahara, but most (85%) crossed the Sahara and spent at least part of the non-breeding season among seven coastal sites in West Africa and one site in the Inner Niger Delta. Although site-use patterns varied among individuals, individuals showed high site fidelity and were consistent in the number of sites they used from year to year. The considerable differences in the spatial distribution of individuals that breed within a kilometre of one another raise questions about the causes and consequences of individual migratory differences. We discuss that full annual cycle tracking of juveniles from birth to adulthood is needed to understand the source of these individual differences. Our results on the spatial distribution of godwits throughout their annual cycle lay an important foundation of information that can be used to help conserve this declining species.

High individual repeatability of the migratory behaviour of a long-distance migratory seabird

“…[ 70 ]), this knowledge also is crucial for facilitating implementation of knowledge-based conservation measures (e.g. [ 7 , 8 ]). As a first step towards understanding the causes and consequences of variation in migratory behaviour of a locally endangered species, the common tern, we tracked 138 migratory journeys undertaken by 64 individual birds.…”

“…[ 6 ]), such that we are in urgent need of knowledge-based conservation measures to protect decreasing populations (e.g. [ 7 , 8 ]).…”

Age‐dependent timing and routes demonstrate developmental plasticity in a long‐distance migratory bird

“…To address this gap, we simultaneously tracked juvenile and adult continental black‐tailed godwits Limosa limosa limosa (hereafter ‘godwits’) from the Netherlands on their south‐ and northward migrations. Godwits breeding in the Netherlands represent a potentially informative study species, because their migratory timing and destination vary considerably and consistently among adult individuals (Verhoeven et al., 2019 ; Verhoeven, Loonstra, McBride, Both, et al., 2021 ). For example, some adults spend the nonbreeding period north of the Sahara, whereas others cross the Sahara to West Africa (Hooijmeijer et al., 2013 ; Kentie et al., 2017 ; Verhoeven, Loonstra, McBride, Both, et al., 2021 ).…”

“…Godwits breeding in the Netherlands represent a potentially informative study species, because their migratory timing and destination vary considerably and consistently among adult individuals (Verhoeven et al., 2019 ; Verhoeven, Loonstra, McBride, Both, et al., 2021 ). For example, some adults spend the nonbreeding period north of the Sahara, whereas others cross the Sahara to West Africa (Hooijmeijer et al., 2013 ; Kentie et al., 2017 ; Verhoeven, Loonstra, McBride, Both, et al., 2021 ). Some adults leave West Africa to fly northward again as early as September while others leave more than 5 months later (Senner et al., 2019 ; Verhoeven et al., 2019 ).…”

“…In combination, these observations indicate that the variation in godwit migratory behaviours may have arisen from either inherited routines or developmental plasticity. Because adult godwits are consistent through time in their migratory behaviour (Verhoeven et al., 2019 ; Verhoeven, Loonstra, McBride, Both, et al., 2021 ), however, we can already rule out phenotypic flexibility as a mechanism for the emergence of individual differences. Therefore, in this study, we focused on disentangling two potential mechanisms for the emergence of individual differences in migratory behaviour: heritable (epi‐)genetic factors and developmental plasticity.…”