1. WHYARE YOU MOVING SO FAST ?
Factors influencing velocity of density shifts in land birds
 Species distributions are shifting towards higher elevations
and the poles in line with climate change forecasts.
 The speed and the direction of range shifts is not equal
among species and some are not shifting at all.
 As magnitude of response to climate change might relate to
species extinction risk, it is important to identify factors that
influences response to climate change.
Migratory species show slower density shifts
than partial migrants and resident species
 Partial migrants and residents can perhaps better utilize
local environmental cues and adjust faster to them.
 Slower density shifts in migratory birds can indicate inability
to cope with the global change.
Lighter species move faster than heavier
 The slower velocity of larger species could be related to
their longer generation time and lower per capita
reproduction.
Do different ecological traits (migratory behaviour, breeding
habitat or weight) explain variation in the velocity of density
shifts in 40 years of line transect data on Finnish land birds.
Line transects are a standardized method to estimate breeding bird densities in Finland. An observer walks ~3-
6 km long route once in June and records all birds. Panel a shows the spatial distribution of line transects dur-
ing 1970-2012 and b shows the temporal variation of census kilometres in different latitudes. The two exam-
ples show the location of the mean weighted latitude (i.e mean centre of weighted density) in the beginning
(green) and end (purple) of the study period for the Blue Tit c) and the Ruff d). Fig. modified from Virkkala &
Lehikoinen 2014Global Change Biology 20: 2995-3003.
The velocity of density shifts in Finnish land bird species
depends on their migration ecology and body mass,but not on
habitat preference. As results are slightly contrasting with
studies of range edge shifts,
we suggest using both whenever possible.
Kaisa Välimäki1
, Andreas Lindén2
& Aleksi Lehikoinen1
1
The Helsinki Lab of Ornithology, Finnish Museum of Natural History, University of Helsinki, Finland,
2
Aronia Coastal Zone Research Team, Åbo Akademi University, Novia University of Applied Sciences, Finland
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QUESTION
CONCLUSIONS
Kaisa Välimäki Email: kaisa.valimaki@helsinki.fi
Helsinki Lab of Ornithology Tel: +358 40 7420704
Finnish Museum of Natural History Twitter: @vulppi
P.O. Box 17 Snapchat: vulppi
00014 University of Helsinki/Finland #TwitterOK