*3.5. Changes to Bird Assemblages with Regard to Primary Food Sources*

Alongside changes to the number of species within bird communities over time, it was also pertinent to investigate whether the proportion of feeding guild types was altered within assemblages due to changing habitats, specifically in those sites where urbanisation increased or greenspace decreased.

A comparison of the proportions of species type for each site where urbanisation was found to have increased is shown in Figure 3.

**Figure 3.** Proportion of species by primary food source at sites where urbanisation has increased.

Subsequent analysis showed an increase in urbanisation resulted in no significant difference in the proportion of species of different primary food sources between 1998 and 2018.

However, in grid cells that had a decreased amount of greenspace, a slight significant difference was shown in those species that chiefly feed on insects, and there is a suggestion of change in those species that primarily feed on fruit, although this was not found to be significant (Table 6).

**Table 6.** Results of paired *t*-test for difference in the proportion of bird species by primary food source between 1998 and 2018 in areas where greenspace has decreased (df = 14).


A comparison of species proportion by primary food source for those grid cell sites where greenspace had decreased over the 20-year period is shown in Figure 4.

**Figure 4.** Proportion of species by primary food source at sites where greenspace has decreased.
