Michele Mendi

Grey Heron is widely distributed throughout much of the Old World, in Europe, Africa and Asia, but absent in the boreal region and deserts(BirdLife International 2021). Migratory behaviour varies from resident to partial migrant or migratory (Voisin 1991) with a cline of increasing migration to the N and E. 

Season of assessment

B

Population trendDecreasing
Population size
(min-max, best estimate)		492000-700000,583000
Red List categoryLC
Franks, S., Fiedler, W., Arizaga, J., Jiguet, F., Nikolov, B., van der Jeugd, Ambrosini, R, Aizpurua, O., Bairlein, F., Clark, J., Fattorini, N, Hammond, M., Higgins, D, Levering, H., Skellorn, W., Spina, F, Thorup, K. Walker, J., Woodward, I. and Baillie, S.R. (1) (2022) Online Atlas of the movements of European bird populations. https://migrationatlas.org EURING/CMS (1) Principal investigator
Map

Overall Connectivity for Grey Heron

Movement patterns vary from ‘local’ dispersal of up to some hundreds of km to true migrations, of up to >6000 km (though most movements <2000 km). Migration is more common N and E populations, even also at more regional levels (Manikowska-Slepowronska et al. 2018). Overall, migration takes places along a NE-SW axis, up to N Africa and the Sahelian belt in W Africa, up to Tchad and Congo Republic. Populations from E and C Europe winter from C and W Europe to N and W Africa; some kind of parallel migration patterns, especially seen in Africa, to a lesser extent in Europe (Campos et al. 2001). N European Grey Herons overwinter mostly from the British Isles to C and W Europe, with some birds found in N and W Africa. Wintering in Iceland has also been reported, particularly of birds ringed in Norway. Birds from the British Isles and W/SW Europe are geerally resident (Campos et al. 2001, Wernham et al. 2002), but with some NE-SW movements as far as Africa. Recoveries in SC/SE Europe are mostly due to the C-European population which migrate on a N-S axis.

Recoveries by Condition for Grey Heron

Currently, around half of the recoveries are of birds seen alive and identified from leg ring(s) or other marks. Before 1960, a remarkable proportion of recoveries were of shot birds (>45%). During 1961-1990, this source of recoveries fell to 26%, though most birds were still found dead. Currently, 44% of the birds are found dead or sick/wounded, with far fewer shot birds (<5%).

Annual Movements for Grey Heron

Post-natal/-breeding dispersal/migration seems to start as early as Jul, when recoveries in Africa not due to summering birds are found. The bulk of migration is detected, however, from late Aug to Oct. Return to breeding grounds seen from Feb, up to Apr. In May, virtually all birds at their breeding sites, except subadult non-breeders, that can remain in their wintering areas or somewhere between these and their future breeding grounds. Recoveries in W Africa exceptional from late Apr onwards.

Connectivity by Month by Region for Grey Heron

Excluding resident birds, most European populations seem to have a similar migration pattern, with first movements in Jul-Aug, following a NE-SW axis, so giving rise to some degree of connectivity, although with high overlap in W/SW Europe and in W Africa, where birds coming from W to C and E Europe overwinter together (Zwarts et al. 2009). Migration from the wintering areas starts in Feb but mostly occurs in Mar-Apr in N European birds. By May, all birds are on their breeding grounds, unless they are non-breeders. Summering in W Africa has been reported, especially for the C and N populations.

Juan Arizaga

References

Statistics Map
N records N individuals N recoveries
Mapped data*
Total available data
*Mapped data include only distant (>= 50 km) recoveries
References Map
2002 . The Migration Atlas: movements of the birds of Britain and Ireland. T. & A.D. Poyser, LondonEditor(s): Wernham, C.V., Toms, M.P., Marchant, J.H., Clark, J.A., Siriwardena, G.M., Baillie, S.R.
BirdLife International 2021 . Species factsheet: Ardea cinerea.
Campos, F., Fernández-Cruz, M., Prósper, J.2001 . Movements of Grey Herons Ardea cinerea to and within the Iberian Peninsula and Balearic Islands. Ardeola 48: 209–215
Manikowska-Ślepowrońska, B., Mokwa, T., Jakubas, D. 2018 . Wintering and Stop-Over Areas of Grey Herons (Ardea cinerea) Breeding in Central Europe: A Ring-Recovery Analysis. Annales Zoologici Fennici 55: 277–285
Voisin, C.1991 . The Herons of Europe. T & A D Poyser, London
Zwarts, L., Bijlsma, R. G., van der Kamp, J., Wymenga, E. 2009 . Living on the edge: Wetlands and birds in a changing Sahel. KNNV Publishing, Zeist

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