SHORT COMMUNICATIONS 
153 
nestlings at two locations near Maracay, Estado 
Aragua, Venezuela. Seven partial or complete 
boluses from Neotropical Palm Swifts were 
obtained from adults captured in a mist net on 
27 July 1976 as they were entering a nesting 
colony in dense dead palm fronds near the base of 
a tree on the grounds of the Hotel Maracay (10 
17' N. 6T 35' W). Boluses were collected from 
the mouth of the netted adult or from a cloth on 
the ground below the net if the bolus was ejected 
by the adult when captured. The exact number of 
nests could not be ascertained due to the density 
of the fronds but there were 28 captures of adults 
at this site. It is unlikely that more than one bolus 
was collected from any single individual. A single 
complete bolus and one partial bolus were 
collected on 16 July 1976 from the mouths of 
Lesser Swallow-tailed Swift nestlings in a nest on 
a roadside overhanging rock cleft in the lower 
portion of Henri Pittier National Park, just north 
of El Limon (10 19' N, 67“ 39' W). These two 
locations are ±9 km apart. No measurements of 
insect abundance in the study area were made as 
part of this study. All of the food boluses were 
stored in alcohol and later examined under a 
dissecting microscope. Identifications were made 
to the family level; the two psocopterans were 
identified as Caecilius ahtillcmm (Turner 1984). 
Body size of prey items was measured with an 
ocular micrometer to 0.1 mm from the tip of the 
head to the tip of the abdomen excluding antennae 
or any caudal appendages. 
RESULTS 
The 381 prey items obtained from Neotropical 
Balm Swifts were distributed among seven Orders 
and 62 families of insects in addition to spiders 
and mites (Table 1). Diptera (52.2%), Homoptcra 
'i8.1%), and Hymenoptera (10.5%) were the 
roost numerous insects recorded. The 108 prey 
Hems obtained from Lesser Swallow-tailed Swifts 
^ere similarly diverse with spiders and five 
Orders of insects distributed among 22 families. 
D ‘Piera (62.2%), Homopteru (17.6%), and Hy- 
roenoptera (1.3.9%) were the most numerous 
insects recorded (Table 1). 
The size of the prey items taken by Neotropical 
Balm Swifts ranged from 0.5 to 7.8 mm with a 
mean ± SD of 2.43 ± 0.9 mm. The size of the 
Prey items taken by Lesser Swallow-tailed Swifts 
ranged from 1.1 to 7.9 mm with a mean ± SD of 
2.77 ± 1.49 IT ,m. There was an abundance of 
smaller prey (<4 mm) and few larger prey items 
in the boluses from both species (Fig. 1). 
DISCUSSION 
Both Neotropical Palm Swifts and Lesser 
Swallow-tailed Swifts took a preponderance 
(>50%) of Diptera in the samples collected. 
There are no detailed data on flight characteristics 
of most insects, but it has been suggested 
(Hespenheide 1975) that Hies are more agile 
fliers than representatives of other Orders with the 
possible exception of some hymenopterans. There 
is some support lor ihe suggestion that deeply 
forked tails in these two swifts are adaptations for 
pursuit of agile prey. Further support can be found 
by examining the prey types taken by three other 
Venezuelan swifts which have square or only 
slightly forked tails. Diptera comprised only 27- 
35% of their diets while Hymenoptera. particu¬ 
larly slower flying winged ants, made up 28-51% 
of their diets (C. T. Collins, unpubl. data). 
The food of the Lesser Swallow-tailed Swift in 
Costa Rica included (lying ants, temutes, small 
beetles, bugs, flies, and wasps (Stiles and Skutch 
1989); in Brazil “small ants and termites 
comprised about 90% of the diet of both species 
(Sick 1993:313). Winged ants and temutes were 
rare or absent from the prey identified in our study 
(Table 1) but expectedly would occur in their 
diets at times when these swarming insects are 
temporarily abundant, 
Diptera made up 43% of the prey items ol the 
White-rumped Swiftlct (Ae rod ramus spodiopy- 
gius) in Fiji (Tarburton 1986b), 24% of the prey 
of this species in Queensland, Australia (Tarbur- 
lon 1993), and 25.8% of the prey of the Glossy 
Swiftlet (Collocalia esculenta) in Malaysia (Hails 
and Amirrudin 1981). Diptera were more com¬ 
monly taken in open areas than in forested areas in 
Fiji, and taken more frequently than their 
representation in aerial insect samplings (Tarbur¬ 
ton 1986b). Diptera averaged 22.1% (range = 
5.0-57.2%) of the prey of seven larger swifts in 
Europe and Africa (Cucco et al. 1993; Collins 
et al. 2009. 2010: Garcia-del-Rey et al. 2010). Only 
the Common Swift (Apus apus) had an occurrence 
above 50% of the prey items and then in only one 
of three separate prey collections (Lack and Owen 
1955: C. T. Collins, unpubl. data). 
Previous studies have also documenled sub¬ 
stantial differences in prey taken by individual 
species on different days or under differing 
weather conditions (Lack and Owen 1955, Hails 
