Long‐term health effects of harness‐mounted radio transmitters in red kites (Milvus milvus) in England

Abstract

In 1989, the Nature Conservancy Council and the Royal Society for the Protection of Birds commenced reintroduction of the red kite (Milvus milvus) according to International Union for Conservation of Nature criteria. Following 22 years of intensive effort, the red kite reintroduction programme has been a success with an estimated 1000 pairs now breeding in England. Post-release health surveillance is ongoing and has been achieved through radio-tracking, monitoring breeding at nest sites and pathological examinations of any red kites found dead. Tail-mounted radio transmitters were fitted from 1989 with harness-mounted radio transmitters being preferentially used since 2000. Since 2000, 180 individuals have been recovered for postmortem examination. Eighteen of these birds had previously had a harness-mounted radio transmitter fitted and four of these (22 per cent) had moderate to severe lesions associated with the presence of the harness and radio transmitter including chronic necrogranulomatous inflammation, deep muscular exposure and distorted muscular conformation. Failure to breed was also reported in two of these individuals over the preceding year(s), although it is not known whether the presence of the harness contributed to this failure. Duration of deployment may have been a significant factor in the formation of these lesions as those with lesions (n=4) had a statistically significant (P=0.009) longer duration of deployment compared to those without lesions (n=14). No lesions were reported in those red kites fitted with tail-transmitters.

Improved Satellite Transmitter Harness Attachment Technique

“…We share concerns expressed by other researchers that use of transmitters must not adversely affect a bird's health or behavior (e.g., Phillips et al 2003, Steenhof et al 2006, Peniche et al 2011. Withey et al (2001) reviewed 96 articles that assessed the impacts of transmitters on wildlife.…”

Humeral Remodeling and Soft Tissue Injury of the Wings Caused by Backpack Harnesses for Radio Transmitters in New Zealand Takahē (Porphyrio Hochstetteri)

“…Other reports of physical injury secondary to backpack radio transmitter harness attachment include free-ranging Spotted Owls (Foster et al, 1992), captive and free-ranging Bald Eagles (Buehler et al, 1995), captive Mourning Doves (Schulz et al, 2001), and free-ranging Red Kites (Peniche et al, 2011), for which all injuries could be attributed to poor and inconsistent fitting of harnesses. It is likely, though, that these injuries have a multifactorial etiology including the mass and dimensions of the device, capture method, handling times, harness configuration, food availability, and length of deployment (Casper, 2009).…”

“…Birds carrying transmitter packages may be experiencing stress that may induce immunosuppression and allow opportunistic infections such as aspergillosis to establish (Peniche et al, 2011). Cutaneous lesions may be associated with pain and inflammation, which may adversely affect wing function for natural behaviors such as mating, intraspecific displays, and predator deterrence.…”

“…Two birds died due to complications of the harness. Peniche et al (2011) found that 22% (4/18) of wild Red Kites (Milvus milvus) that had been deployed with a body-loop style backpack harness had moderate to severe harnessassociated lesions at necropsy. These included chronic necrogranulomatous inflammation over the spine and sternum, deep pectoral muscular exposure, and distorted muscular conformation with a statistically significant correlation between formation of lesions and duration of harness attachment.…”

Effects of satellite transmitters on survival in Snowy Owls <i>Bubo scandiacus</i>

“…Barron et al 2010, Vandenabeele et al 2011. So far, tracking instruments have been associated with effects like increased energy use, impaired reproduction, higher stress levels, increased mortality rates and severe lesions in equipped individuals (Barron et al 2010, Müller et al 2011, Peniche et al 2011, Vandenabeele et al 2011.…”