Figure legends:
Figure 1: Social networks across multiple situations. A
hypothetical example of social interactions among vultures in different
social situations: co-flying in blue, nocturnal ground interactions,
(i.e., co-roosting) in green, and diurnal ground interactions (e.g.,
co-feeding) in yellow. Solid lines within each social situation indicate
interactions within the social situation and black-dotted lines between
social situations connect occurrences of the same individual. Dashed
orange lines connect individuals to food sites to show how spatial
proximity can be used to infer social interactions, for example when
co-feeding. An aggregate network at the top, in gray, combines all
interactions from the different social situations.
Figure 2. Inferring interactions from movements. (A) Location
of study site - small red square - on a Satellite image of Earth (from
GoogleEarth). (B) Satellite image (from GoogleEarth) of the study area
in southern Israel (the Judean and Negev deserts) with example
trajectories of vultures that interacted in two different social
situations. Blue lines are movement trajectories of vultures that
engaged in co-flight. The word ‘co-flight’ appears next to the two
regions of their trajectories that overlapped in time and space -
deeming them co-flight interactions. Green lines are movement
trajectories of two vultures that roosted at the same roost overnight
and therefore are considered to have a nocturnal ground interaction. The
small green polygon to the bottom right of the word ‘Roost’ is the roost
in which they both spent the night. Note that these two vultures did not
engage in co-flight interactions. (C) Photo of a griffon vulture with a
GPS tag attached to its back (circled) and wing tags (photo credit:
Tovale Solomon).
Figure 3. Social networks in different social situations.Networks of 29 individually tagged vultures during the breeding season
(December 2020 - June 2021). From left to right the situations include
co-flight (blue), nocturnal ground interactions (green), diurnal ground
interactions (yellow), and an aggregate network that combines
interactions in all three situations (gray). Nodes depict individual
vultures and the position of each node (individual) is maintained in all
four networks. As an example, the identities of three individuals are
specified in all four networks. Lines connecting nodes indicate that
individuals interacted within a social situation, and line thickness
corresponds to association strength.
Figure 4: Individuals differ in their social position across
social situations. Annular representation of the interaction strength
of 29 tagged vultures in the breeding season of 2021. Three rings
represent the three social situations: co-flight (blue hue), nocturnal
ground interactions (green hue), and diurnal ground interactions (yellow
hue). The outer ring represents the aggregate network (gray hue). Darker
shades indicate a higher rank of interaction strength. Each slice in the
ring corresponds to one individual. Some individuals may be important in
one social situation but not in others. For example, of the three
individuals that are highlighted, J15w has a strength that is highly
ranked in the diurnal ground interactions but not in the other social
situations. Similarly, J36w is highly ranked in the nocturnal ground
interactions but not in other social situations. Finally, individual
J06w is highly ranked in co-flight interactions but not in other
situations. Similar plots for degree and PageRank are provided in Fig.
S1.
Figure 5. Relationship between centrality in the aggregate
network and each social situation. Correlation between centrality
measures (degree (A, D, G), strength (B, E, H), and PageRank (C, F, I))
in the aggregate network (x axes) and each of the three social
situations (y axes): (A-C) co-flight, (D-F) nocturnal ground
interactions, and (G-F) diurnal ground interactions. Each point is an
individual vulture and points were jittered (0.4) along the x and y axes
to improve readability in the plots of degree (A, D, G). Lines represent
the correlations and the shading around the line is the 95% confidence
interval computed using ggpubr() function of the ggplot R package
(Wickham, 2011) with the lower confidence limit being 1±0.95/2
percentiles.
Figure 6. Comparing observed and expected correlations.Observed (diamonds) and randomized reference distribution (violins) of
Spearman’s correlation coefficient (ρ ) between three centrality
measures: degree (A), strength (B), and PageRank (C) in each of the
three social situations: co-flight (blue), nocturnal ground interactions
(green), and diurnal ground interactions (yellow). Vertical black lines
on the violin plots depict the 95% quantiles of the reference
distribution. Asterisks to the right of each plot denote statistically
significant differences between the observed values and chance
distribution using a two-sided test. Violin plots were created using
ggplot2 (Wickham, 2011).