Hypotheses and predictions tested with summary of outcomes.

*<p>in relation to their presence on trails containing active marking trees.</p><p>AM – adult male, AF – adult female, SUB – subadult, F+Y – female with dependent young, BS – breeding season, NON-BS – non-breeding season, Y/N – yes or no, P – partially supported.</p

χ² for association tests displaying total behavioural events per age sex class for the breeding and non-breeding season.

<p>+/− indicates significantly more/less than expected (<i>p</i><0.05).</p

Classification to age sex class of individuals captured on images and directly observed.

*<p>noted if known.</p

Behavioural frequencies in relation to trail use.

<p>Total observed events of marking (A, B) and investigation (C, D) by each age sex class, compared to their expected frequency in relation to their presence on trails containing active marking trees. Comparisons during the breeding (A & C) and non-breeding season (B & D). *** indicates <i>p</i><0.001 in subdivided testing, ** <i>p</i><0.01 and * <i>p</i><0.05.</p

Description of the three stages of juvenile gill development based upon observations during this study.

<p>The age (months) at which individuals begin to display particular structures/developments is approximate and no attempt has been made to postulate when development of certain structures begins if they were not directly observed during this study. The number of inner demibranch (ID) and outer demibranch (OD) filaments are the number observed during this study and may differ depending upon population or other parameters.</p

Main anatomical features of juvenile mussels.

<p>a) Foot (FO), unreflected filaments (FI), gill axis (GA), left and right labial palps (LP). b) Distal tips of filaments are joined to each other by thin tissue connections (arrow heads); c) Gill reflection of the inner demibranch. Thin tissue connections join filaments at the ventral bend (VB) and the thicker fused dorsal bend (FDB) joins the terminal ends of the ascending arms. All three cilia types are present on the ascending limbs (AL); lateral cilia (LC), laterofrontal cirri (LFC) and frontal cilia (FC). The ascending limb is longer on medial filaments compared to those at either anterior or posterior ends (to the left and right of frame). Other features of note are the filament abfrontal surface (AS), descending limb (DL) and mantle (MA); d) Oral groove on inner demibranch (left) and absence of groove on outer demibranch (right); e) Ciliary junctions between approximately filaments 11–14 (*), after which tissue junctions were present (†); f) Right ID, OD and labial palps (LP). Inset: Labial palps are highly ciliated on the inner surface but devoid of cilia externally.</p

Summary information about the ranges of shell length (mm) and number of inner demibranch (ID) filaments for the different age cohorts.

<p>The number of specimens considered is also provided (n).</p

Land cover resistance values based on previous least-cost modelling studies and resistance set based on expert opinion.

<p>*Note the resistance scores given in Verbeylen et al.'s (2003) study are for red squirrels in an urbanised matrix and are used for comparison.</p><p>Land cover resistance values based on previous least-cost modelling studies and resistance set based on expert opinion.</p

Interfilamentary space vs length (mm) and age (months).

<p>There was no significant trend of interfilamentary space with length nor age.</p

Average probability of grey squirrel presence according to land cover type.

<p><i>p</i> =  mean predicted probability of presence according to habitat type.</p><p>Average probability of grey squirrel presence according to land cover type.</p