Live decoys: an old but effective tool for attracting, capturing, and studying free-living passerines

Rehabilitation and release of confiscated songbirds into the wild: A pilot study

“…Sepsis was also observed in our subjects, as well as aspergillosis and candidiasis which are expected diseases among songbirds undergoing the usual stressors in illegal trafficking. Wild birds may also die from acute stress-induced cardiogenic shock due to decreased circulating plasma, physical restraints, or hypovolemic shock resulting from insufficient blood volume caused by acute hemorrhage or excessive fluid loss ( 34 , 84 ). Given the fighting dynamic we already mentioned, we could plausibly attribute death to cardiogenic shock to explain some of the inconclusive losses with no inflammatory or infectious findings ( Supplementary Table 5 ).…”

“…Before removing them from their cages to handle them, we observed their behaviors toward handlers to roughly classify traits into (1-tame) bird perching and feeding even when the cage was held by handlers, (2-semi-wild or undefined) bird perching and feeding when handlers remained about 5 m away from the cages, or when birds were housed in a collective cage, and (3-wild) bird fluttering, not perching or feeding when handlers remained about 5 m from the cage. Regarding their dominance behavior, such as vocalizations (repeated usual song, song switching, and long, loud whistles and calls) or fighting postures (ruffled chest and head feathers, fully raised crests, half-open beaks pointing upwards) ( 34 ) in response to playback of conspecific vocalizations or face-to-face conspecific challenges, birds were initially classified as (1-dominant) vocalizing and/or fighting postures, (2-semi-dominant or undefined) no vocalizing but also no signs of submission, and (3-submissive), mute birds with ruffled forehead feathers, lowered heads, retracted tufts, low chirping, and/or open lowered wings. Next, the birds were marked with split metal rings.…”

“…During the health screening, all birds were examined for external parasites and proliferative skin lesions typical of avian pox. Rectrices and primary feathers were checked, broken feathers removed, long nails trimmed, and individual samples (feces, oropharyngeal swabs, and blood) collected, as described previously ( 34 ). Blood samples were only collected from birds weighing approximately 40 g. All the birds were dosed with Zooserine ® oral pills (tetracycline hydrochloride 0.18 mg/g, chloramphenicol 0.133 mg/g, and furazolidone 0.03 mg/g) and occasional tarsal hyperkeratosis was treated by manually applying Dolemil ® (potassium sulfide 3%) ointment.…”

“…Post-release monitoring was mostly performed on the farms, where two project members covered 5 to 10 km a day. To attract target species and recapture released birds, we used live decoys, mist nets, cages fitted with netted trapdoors, and loop snares, as previously described ( 34 ). Recapture was necessary for identifying ring numbers and assessing recorded data (entry, release, and distance moved from release site, Supplementary Table 1 ).…”

“…In addition, we also followed tips from local people about the sightings or location of ringed birds. After hearing or sighting a target species and using binoculars to verify ringed subjects, the capture arena was installed ( 34 ). If a target bird approached the car very quickly, we simply installed netted trapdoors and snares.…”