Diet breadth and overlap in three sympatric aerial insectivorous birds at the same location

Figures & data

Table 1. General percentage composition of major food types/order of insects (number and biomass) in the diets of nestlings of three species of aerial feeding birds breeding at the same location in southwestern Poland.

Prey type^a	Number of prey (%)			Biomass of prey (%)
	Swift (n = 5956)	Swallow (n = 2256)	House Martin (n = 7062)	Swift (11 686 mg d.w.)	Swallow (10 826 mg d.w.)	House Martin (26 695 mg d.w.)
Diptera	2.3	18.2	5.4	7.1	17.5	5.7
Curculionidae	65.7	27.3	25.3	63.1	23.0	32.0
Chrysomelidae	3.4	0.8	7.6	4.7	0.4	4.0
Staphylinidae	3.2	1.6	3.4	1.5	0.3	0.8
Coccinellidae	0.1	0.1	9.3	0.3	0.2	25.4
Carabidae	0.2	2.4	2.2	0.6	5.1	2.4
Coleoptera other	4.3	9.0	13.2	1.4	5.9	3.6
Ichneumonidae	5.7	8.5	7.1	5.7	4.3	4.1
Ants	3.9	19.5	15.1	1.4	2.8	2.6
Chalcidoidea	5.0	0.9	3.9	0.7	0.1	0.3
Hymenoptera other	0.6	3.8	1.7	0.3	10.2	0.4
Pentatomidae	1.0	5.1	2.4	10.8	28.9	16.3
Heteroptera other	1.9	2.3	2.6	1.6	0.7	1.1
Other insects	2.8	0.4	0.8	1.1	0.6	1.4

Analysis based on all analysed faecal sacs for each species: Swifts (n = 98), Swallows (n = 138) and House Martins (n = 238).

^aCategory ‘Other insects’ comprises Homoptera and some other insects, as well as spiders; for the complete list of prey found, see Electronic Appendix 1.

Table 2. Comparison of proportions (%) of 14 main food types (in terms of their number) per individual faecal sac (number of faecal sacs given in brackets) from nestlings of three species of aerial feeding birds breeding at the same location in southwestern Poland.

	Swift (n = 98)			Swallow (n = 89)			House Martin (n = 171)
Prey (taxonomy)^a	Mean	95% CI	Median	Mean	95% CI	Median	Mean	95% CI	Median
Diptera	4.6	2.5–6.7	0.7	27.8	21.8–33.7	20.0	7.6	15.9–9.3	4.7
Curculionidae	53.2	47.4–59.0	54.8	19.3	13.6–24.9	9.1	15.9	13.0–18.8	9.5
Chrysomelidae	4.3	3.0–5.6	2.0	0.9	0.2–1.5	0.0	7.4	5.2–9.6	0.0
Staphylinidae	4.8	2.6–7.0	0.0	1.6	0.2–2.9	0.0	3.3	2.4–4.1	0.0
Coccinellidae	0.1	0.0–0.2	0.0	0.2	0.1–0.5	0.0	13.0	11.0–15.1	8.7
Carabidae	0.3	0.1–0.6	0.0	2.8	1.5–4.0	0.0	2.9	2.1–3.7	0.0
Coleoptera (other)	4.7	3.3–6.2	1.8	11.2	8.0–14.4	6.9	15.2	12.9–17.5	12.0
Ichneumonidae	7.4	5.3–9.5	4.2	10.4	7.6–13.2	6.3	9.8	7.8–11.8	6.3
Formicidae (ants)	6.0	4.2–7.9	2.0	13.1	8.5–17.7	0.0	11.9	9.3–14.6	3.1
Chalcidoidea	7.3	5.3–9.4	3.6	1.2	0.4–1.9	0.0	4.0	3.2–4.9	0.0
Hymenoptera (other)	0.8	0.3–1.4	0.0	4.9	2.9–6.9	0.0	1.7	1.1–2.4	0.0
Pentatomidae	1.3	1.0–1.7	0.0	3.9	2.3–5.5	0.0	3.4	2.7–4.2	2.0
Heteroptera (other)	2.4	1.7–3.2	1.1	2.6	0.8–4.4	0.0	3.1	2.3–3.9	0.0
Other insects	2.6	0.6–4.6	0.0	0.3	−0.2–0.9	0.0	0.6	0.3–0.9	0.0

^aCategory ‘Other insects’ comprises Homoptera and some other insects, as well as spiders.

Figure 1. Comparison of the main characteristics (indices) of the diet (mean ± se) calculated per individual faecal sac of nestlings of Swifts (n = 98), Swallows (n = 89) and House Martins (n = 171) breeding at the same location in southwestern Poland.

Table 3. Comparison of body weight of prey (mg d.w.) identified in all analysed faecal sacs of nestlings of three species of aerial feeding birds breeding at the same location in southwestern Poland calculated for the complete list and number of insect prey found, see Fig. 1 and Electronic Appendix 1 for numerical details.

Prey (taxonomy)^a	Swifts (n = 98)			Swallows (n = 138)			House Martins (n = 238)
	Mean	95% CI	Median	Mean	95% CI	Median	Mean	95% CI	Median
DIPTERA (total)	9.3	8.8–9.8	9.2	8.9	8.3–9.5	9.2	9.0	8.3–9.6	9.2
Curculionidae	1.9	1.7–2.1	0.7	4.1	3.2–4.9	0.7	4.8	4.3–5.3	0.7
Chrysomelidae	2.7	2.5–2.8	3.4	2.6	1.9–3.2	3.4	2.0	1.9–2.1	1.8
Staphylinidae	0.9	0.8–1.0	0.5	1.1	0.9–1.3	1.4	0.9	0.8–0.9	0.5
Coccinellidae	2.7	−19.4–24.7	2.7	8.4	−58.2–75.1	8.4	10.7	10.2–11.1	13.7
Carabidae	7.2	1.1–13.3	8.5	10.1	8.2–11.9	8.5	4.2	3.1–5.2	1.2
Coleoptera other	0.7	0.4–0.9	0.4	3.8	2.6–5.1	0.4	1.2	0.9–1.5	0.3
COLEOPTERA (total)	1.8	1.6–2.0	0.7	4.2	3.6–4.9	0.7	4.4	4.1–4.7	0.7
Ichneumonidae	2.0	1.9–2.1	2.4	2.4	2.4–2.4	2.4	2.2	2.1–2.2	2.4
Formicidae (ants)	0.7	0.6–0.7	0.6	1.0	1.0–1.1	1.2	0.7	0.6–0.7	0.6
Chalcidoidea	0.3	0.8–0.9	0.2	0.3	0.2–0.3	0.2	0.2	0.2–0.3	0.2
Hymenoptera other	0.9	−0.2–1.9	0.3	13.2	10.8–15.6	20.6	0.8	0.3–1.3	0.3
HYMENOPTERA (total)	1.0	1.0–1.1	0.6	2.8	2.4–3.2	1.2	1.0	0.9–1.0	0.6
Pentatomidae	21.7	19.4–24.0	26.2	27.0	25.1–28.8	36.3	25.8	24.2–27.4	26.2
Heteroptera other	1.7	1.6–1.8	2.0	1.6	1.4–1.7	1.8	1.8	1.7–1.8	2.0
HETEROPTERA (total)	8.6	6.9–10.2	2.0	19.1	17.0–21.4	14.3	13.7	12.2–15.3	2.2
OTHER INSECTS	0.9	0.8–1.1	0.6	6.8	3.0–16.6	2.9	17.9	9.5–26.4	11.7
ALL PREY	2.0	1.8–2.1	0.7	5.4	5.0–5.9	1.2	4.0	3.8–4.2	0.7

^aCategory ‘Other insects’ comprises Homoptera and some other insects, as well as spiders.

Figure 2. Comparison of the frequency distribution of insect prey weight taken by three species of aerial feeding birds breeding at the same location in southwestern Poland based on known weight of all identified prey, see Electronic Appendix 1.

Figure 3. Comparison of proportions of various groups of insects in terms of their ecological (a) and economic (b) roles in the diet of three species of aerial feeding birds based on the complete list of insect prey found, see Electronic Appendix 1; total number of prey assigned to at least one role is indicated.