**2. Previous knowledge**

Mammals, birds, reptiles, amphibians, and invertebrates are roughly the usual prey for owls, but what is the preferred prey of each species? There is published information on nine out of the 29 species of owls occurring in Ecuador; the remaining 20 species have only anecdotal data, whereas for two there is virtually no information on their diet in Ecuador. Given that there are few peer-reviewed publications about the diet of Ecuadorian owls, in this section, we also include gray literature, such as conference papers or thesis, and unpublished information compiled by the authors in the field and in a revision of museum specimen labels. The level of taxonomic identification of the prey is variable, according to secondary information. We have tried to identify our own observations to the highest taxonomic level possible.

#### **2.1** *Tyto furcata*

*T. f. contempta*: There are only three specimens (MECN 6833, 8773, 8678) of this common and widespread taxon with stomach content information. They contained remains of Coleoptera and rodents. Stomach content of MECN 6992 mentions herbs as the only item, so it cannot be considered secondary content (*i.e.*, stomach contents of a prey); it could have been accidentally ingested when hunting.

There are two studies of its diet using pellets, but from a mammalogy approach, so non-mammal preys were overlooked. These studies underline the high consumption of rodents [11, 12].

This is the best-studied species in Ecuador, most studies being based on pellets analyses, and covering as varied habitats as cities [13, 14], rural areas, or agricultural fields in the Pacific lowlands [15–17] and Andean valleys [18]. However, there is no long-term research on its diet or a broader study aiming to understand feeding preferences in relation to prey abundance and availability.

The predominance of rodents in the diet of *T. furcata* is consistent with studies in other countries [18 and cites therein]. However, this species is also opportunistic, preying upon other kinds of prey, including bats [14] or high number of birds in agricultural and open habitats [18]. Six pellet studies showed the following quantitative data:

In Cuenca, Azuay province, n = 245: 249 introduced rodents, 95 native rodents, 7 birds, and 93 Coleoptera items [13]. In Pallatanga, Chimborazo province, n = 61: 25 introduced rodents (*Mus musculus* and *Rattus* sp.), 132 native rodents, 2 *Sylvilagus andinus*, 3 birds, and 2 reptiles. In Calceta, Manabí province, n = 46: 34 introduced rodent (*M. musculus*)*,* 99 native rodents, 2 *Proechimys decumanus,* 1 *Marmosops* sp., and 1 *Sylvilagus daulensis* [15]. Another study in Cuenca, Azuay province, n = 32: 100 introduced rodents, 29 native rodents, 1 vampire bat *Desmodus rotundus*, 2 birds, 4 reptiles, and 18 Coleoptera [14]. In Zapotillo, Loja province, n = 65: 130 *M. musculus*

*What Do We Know about the Diet of Ecuadorian Owls? DOI: http://dx.doi.org/10.5772/intechopen.108594*

and 42 native rodents [16]. In another sample from Calceta, Manabí province, n = 30: 57 native rodents, 7 bats, and 1 dove [17]. The largest pellet sample studied in Ecuador included 361 pellets and 664 g of pellets debris from San Antonio and Tababela, Pichincha province. This sample included 86 introduced rodents, 803 native rodents, 67 *S. andinus*, 93 birds, 6 reptiles, and 63 insects [18].

*T. f. punctatissima:* The Galapagos endemic subspecies is little studied as compared to other Galapagos land birds [19]. The first available information was provided from a sample of 1217 pellets collected in Santa Cruz and Isabela islands [20]. It reports 2230 mammal prey (mostly *M. musculus*), 81 birds, 10 reptiles, and 2440 invertebrates*.* A second study reported 90% of rodents, 14% of insects, and less than 1% of birds from a sample of 104 pellets collected on Santa Cruz Island [21, 22]. Details of specific prey found in the latter study will be published elsewhere.

#### **2.2** *Megascops albogularis*

*M. a. albigularis:* Stomach contents of three museum specimens (MECN 6150, 7755, 7760) contained remains of a myriapod, also orthoptera, and other insects [23].

There is no other available information on its diet, but one wild pair is being fed raw chicken pieces in Zuro Loma, Pichincha province (**Figure 1**). The behavioral implications of this artificial feeding are not known, but there are records of carrion consumption by owls, including *Megascops* species [24]. This event might allow close observations of this owl by birders and nature lovers, which could increase their empathy and appreciation, and promote its conservation. This case deserves further study.

*M. a. macabrum*: Stomach contents of one museum specimen (MECN 772) had insect remains [23].

#### **2.3** *Megascops choliba crucigerus*

Stomach contents of one museum specimen (MECN 3994) had insect remains [23]. Another museum specimen (MECN 9633), not included in the cited work, also had insect remains.

#### **2.4** *Megascops koepckeae*

An unreported number of pellets of this species was only recently reported for Ecuador [25], collected in Loja city, and contained mainly insects and the introduced *Mus musculus* [26]. There is one record of nestling being provisioned with one scorpion and one frog [D. Pacheco pers. obs.].

#### **2.5** *Megascops ingens*

*M. i. ingens:* Stomach contents of five museum specimens (MECN 773, 7288, 7758, 7763, 7773) contained remains of the order Orthoptera (crickets, grasshoppers) and other unidentified insects [23].

*M. i. colombianus:* One individual mist-netted in Río Guajalito, Pichincha province, carried an opossum *Marmosops impavidus* on its talons, of which the entire head and forelimbs had already been eaten [27]. There is an additional observation of Carabidae (Coleoptera) remains in an abandoned nest, in Nanegalito, Pichincha province (JF. Freile pers. obs.).

#### **Figure 1.**

Megascops albogularis *feeding on raw chicken pieces in a private reserve in Pichincha. Photo: Courtesy of Edison Buenaño.*

### **2.6** *Megascops petersoni*

Stomach contents of six museum specimens (MECN 774, 775, 7752, 7762, 7866, 7867) had remains of the order Orthoptera (crickets, grasshoppers) and other unidentified insects [23].
