DISEASE SUMMARY PAGE

Foreign Body Entanglement & Snaring (With special reference to Eurasian badgers, Hedgehogs and Cranes)
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Summary Information
Diseases / List of Physical / Traumatic Diseases / Disease summary
Alternative Names See also: Hook and Line Injuries, Foreign Body Ingestion
Disease Agents
  • Snares, set legally or illegally.
  • Discarded fishing line.
  • Netting used to protect plants, pea or runner-bean netting, cricket nets, tennis nets, discarded netting etc.
  • Tin cans, particularly if the lid is not completely removed.
  • Yoghurt pots and similar containers.
  • Discarded baler twine, string etc.
  • Hair and wool which may become entangled around limbs
  • Plastic 'four-pack' (UK) or 'six-pack' (USA) drinks can containers, 
  • Plastic rings from necks of drinks bottles, plastic bags and any other object with a loop discarded into the environment.
    • Plastic objects are particularly hazardous as they do not break down in the environment.
    • 'Tamper-proof' rings from the necks of drinks bottles may lodge around the head of birds. These frequently have sharp plastic 'teeth' on the inside, making it difficult for the bird to dislodge.
  • On crane bills, elastic bands, "O" rings, shotgun shells, discarded drinks cans, golf ball cores and other objects. (P87.8.w5)
  • Badly fitting leg rings on birds can also cause injury.

N.B. Objects may be divided into two broad categories:

  • Snares and other loops which are fixed to a solid object and which may pull tighter as the animal attempts to escape.
  • Objects which are not fixed to any solid object but which may cut into the animal due to sharp edges or because they remain at a fixed size while the animal grows.

(B36.51.w51, B228.9.w9, B259.w9, B337.3.w3, P8.3.w1, V.w5, V.w6, V.w26)

Infectious Agent(s) --
Non-infectious Agent(s) --
Physical Agent(s)
General Description Clinical signs:
  • Snare, other line or other object visible caught around the head, neck, body or limb.
  • In juveniles, the entangled part of the body may be constricted as the animal grows.
  • Objects caught in the mouth or round the bill may interfere with eating, drinking and preening.
  • Snares and other loops attached to a fixed object may cause severe injury to underlying structures.
  • Linear skin and tissue damage underlying the site of the snare/entangled object.
    • Skin damage may or may not be evident at the time of initial presentation.
    • Deeper tissues may or may not be visible and visibly damaged at the time of presentation.
  • In longer-standing snare/entanglement wounds secondary Myiasis may be present.

(B36.51.w51, V.w5, V.w6).

In Hedgehogs:
  • Entanglement in netting (cricket nets, tennis nets, netting for runner beans etc.) is common.
  • Often get caught in plastic rings (from e.g. "four-packs"), or ends cut off plastic pipes.
  • Often get yoghurt pots, tin cans and similar food containers caught on their heads while scavenging for food. A leg may also get caught in a tin, for example between the rim and the partially-opened lid.
  • A tangled leg may be partially or totally severed.
  • The throat may be damaged.
  • Juveniles may be wasp-waisted due to a constricting object around which they are still growing. 

(B228.9.w9, B259.w9, B337.3.w3)

In Badgers:
  • Snare injuries are common
    • These may involve the limbs, head and neck, or abdomen.
    • Pressure necrosis of underlying tissues may not be visible for several days after the initial injury.
    • Animals from which a snare have been removed must be kept for several days for observation, not released immediately 
    • (J60.2.w3)
    • It is illegal to use a snare on badgers in the UK therefore cases should be reported to the local police station, National Federation of Badger Groups and RSPCA on their Snaring Incident Report form (provide link and check the name of the form). 
    • It is vital that the badger is caught and secured within an enclosed area before the snare is removed, often requiring general anaesthesia. Releasing the snare before the badger is contained must be avoided because this could allow it to escape before examination for underlying wounds is possible. It is also critical that the technique of capture does not allow the badger to escape with the snare still attached to its body. (V.w26)
In Cranes
  • Entanglement with wire fences was the cause of death in 12/143 (7.2%) free-ranging Grus grus - Common crane from Germany, 1998-2008. [2011](J1.47.w5)
  • In resident Grus americana - Whooping cranes in Florida, one subadult female was caught in a fence with a resulting hip dislocation and skin laceration; another was also caught on a barbed wire fence. (P87.8.w5, P87.11.w2)
  • Two sandhill cranes in Florida were found entangled in woven-wire fences with a strand of barbed wire on the top - each crane had a foot trapped between the barbed wire and the top strand of the woven wire. (P87.8.w5)
  • A sandhill crane in Florida became entangled in an electric fence and was electrocuted. (P87.8.w5)
  • A whooping crane which became trapped between concrete feed troughs apparently panicked with resultant compound fracture of the tarsometatarsus, and died during surgery.  (P87.8.w5)
  • Lameness and/or foot swelling was seen in resident Grus americana - Whooping cranes in Florida associated with entanglement in monofilament lines. Clinical signs resolved over time although one crane lost two thirds of the hallux on the affected foot. (P87.11.w2)
  • Entanglement in a fence was recorded as the cause of death for one of 17 deaths (11 with cause known) out of 38 monitored free-ranging, parent-reared Florida sandhill crane (Grus canadensis - Sandhill crane) chick in a study 1996-1999 in Florida, USA. (P87.10.w7)
  • Entanglement of the bill with various man-made objects has been recorded for Grus canadensis - Sandhill cranes and Grus americana - Whooping cranes in Florida, sometimes with the object holding the crane's bill closed or otherwise damaging the bill and/or interfering with the crane's ability to feed. In a number of cases in which the item was firmly fixed on the bill it was considered that without human intervention the entanglement would have been fatal. (P87.8.w5)
  • Entanglement of a leg with monofilament line wrapping around the leg and foot was noted in two whooping cranes and one sandhill crane in Florida, while another whooping crane had cotton string around a leg. The presence of the line was first suspected due to abnormal behaviour of the cranes such as limping and reduced activity. On examination, the leg and foot distal to the line was swollen, indicating obstruction of blood flow. (P87.8.w5)
  • A Grus grus - Common crane had  a strand from the release aviary shade-netting become tangled around her tongue and cut her tongue. (D449)
  • A released  Grus grus - Common crane  became tangled in fishing tackle which hung from the bird's beak for about 12 days, after which he was seen without it and appeared fine. During the period of entanglement the crane appeared able to feed but became tatty-looking, being apparently unable to preen properly. (D451)
  • Mud entrapment: In 2001, 87 Grus canadensis - Sandhill cranes become trapped in deep, saturated silt and clay exposed following drainage of a reservoir for repairs in New Mexico. Ten birds managed to drag themselves to the shore using their wings, but nine of these died and were scavenged, or were predated; one was captured, treated by a rehabilitator and released. 16 cranes were retrieved using a flat-bottomed boat and a modified outboard motor, and treated; 13 of these survived. On retrieval, those which had been mired for several days were dehydrated (Dehydration), hypothermic (Chilling / Hypothermia) and hypoglycaemic. Several had bruising on the carpi due to efforts to use their wings to "row" themselves through the mud. Many were too weak to stand. [2005](P87.9.w3)
Further Information Animals from which a snare have been removed must be kept for several days for observation, to ensure that no tissue breakdown caused by pressure necrosis develops at the site of the snare constriction; they should NOT be released immediately (J60.2.w3, V.w26)

Treatment:

  • Simply removing the object may be all that is required if the underlying structures are not damaged.
  • Where a snare or another object acting as a snare is involved, it is important that the animal not released immediately after removal of the snare as damage to tissues underlying the snare (from pressure necrosis) may not be visible initially. Keeping the animal for several days is advisable.
  • If a snare or a line or piece of netting or other object acting as a snare is removed in the field it is important to ensure that the animal is securely captured before the snare is removed and that it does not escape with the snare still around the animal.

In Badgers:

  • It is illegal to use a snare on badgers in the UK therefore cases of snaring should be reported to the local police station, National Federation of Badger Groups and the RSPCA on their Snaring Incident Report form (see the Appendix of B152 - Problems with Badgers - full text available). (V.w26)
  • It is vital that the badger is caught and secured within an enclosed area before the snare is removed, often requiring general anaesthesia.
    • Releasing the snare before the badger is contained must be avoided because this could allow it to escape before examination for underlying wounds is possible. 
    • It is also critical that the technique of capture does not allow the badger to escape with the snare still attached to its body. 
  • Animals from which a snare have been removed must be kept for several days for observation, to ensure that no tissue breakdown caused by pressure necrosis develops at the site of the snare constriction, not released immediately (J60.2.w3, V.w26)
  • Fluid therapy for dehydration may be required dependent on the duration of the period trapped in the snare. (V.w26)

In Hedgehogs:

In Cranes
  • Grus canadensis - Sandhill cranes which had been trapped for up to four days in deep, saturated silt and clay were treated as follows: [2005](P87.9.w3)
    • Immediately after removal from the mud, cranes were wrapped in blankets for warmth and to facilitate handling.
    • The external nares were cleaned of caked mud using warm water.
    • On arrival at the heated, indoor treatment facility, warm running water was used to remove caked mud from the feathers and the crane was assessed. Those which had been mired for several days were dehydrated, hypothermic and hypoglycaemic. Several had contusions on the carpi due to efforts to use their wings to "row" themselves through the mud. Many were too weak to stand.
      • Those which had been trapped for least time only required cleaning; they were then placed in a secluded barn, started eating and were released after a few days.
    • Cranes were gavaged (Gavage / Tubing of Birds) with 60 mL water containing 10 mL 50% dextrose. Enrofloxacin was injected (5 mg/kg) as antibiotic cover, Vitamin E (5 mg/kg) injected to help reduce the risk of Capture Myopathy and Dexamethasone (0.5 mg/kg) given to treat stress and shock.
    • Cranes were bedded on grass hay in a heated room while they were too weak to stand.
    • After 24 hours, cranes were gavaged with 60 cc Vivinex Plus (elemental diet, easily absorbed); some of the cranes were further cleaned of mud.
    • Later the same day, cranes were gavaged with 60 mL Hills AD. Enrofloxacin injection was repeated.
    • The following day (48 hours) most cranes still were showing no interest in eating; a further 60 mL Hills AD was given in the morning. By afternoon, they were showing some interest in eating.
    • Once eating, cranes were moved to a secluded location with access to a covered outdoor area. here the cranes were calmer and appeared to eat better.
    • Only three birds died; these had all been trapped for more than 24 hours; one developed capture myopathy and two died from probable respiratory failure after inhaling mud.

    (P87.9.w3)

  • In a resident Grus americana - Whooping cranes in Florida, a hip dislocation resulting from entanglement in a fence resolved during transit for treatment; laceration of the skin on the feathered tibia was sutured and the crane was released after a month. (P87.8.w5, P87.11.w2)
  • In resident whooping cranes in Florida, a crane which was found caught in a barbed wire fence was released by the owner of the property and recovered in the wild. (P87.8.w5)
  • In cases where cranes have had their bill impaled in an object, interfering with feeding, capture of the crane and removal of the object from the bill. (P87.8.w5)
  • In whooping cranes and a sandhill crane in Florida, with line wrapped around a leg/foot, the cranes were captured and the line removed. All survived, but one whooping crane lost its hallux, another had permanent swelling and scarring of the lower leg, and the sandhill crane lost its middle toe. (P87.8.w5)
  • A strand from the release aviary shade-netting was removed from around the tongue of a Grus grus - Common crane . (D449)

Prevention:

  • Entanglements can be prevented by responsible disposal of rubbish (trash), particularly plastics.
    • Four-pack or six-pack containers should have each ring cut through or broken before being thrown away, even into a rubbish bin (trash can), as should bottle neck rings that have become detached from the bottle.
    • Tin cans should have the lids cut off fully before being discarded. These and yoghurt pots etc. should be fully emptied and if possible rinsed before being thrown away to decrease their attractiveness to scavengers.
    • (B36.51.w51, V.w5)
  • Mud entrapment: Hazing techniques (crackers, whistling and pyrotechnic shells, and search lights) were used to discourage cranes from landing on what appeared to be a useable shallow wetland for roosting but was actually dangerous deep saturated clay and silt left after a reservoir was drained for repairs. (P87.9.w3)
Techniques linked to this disease

Hazing:

Host taxa groups /species

[N.B. Miscellaneous / Traumatic Diseases tend to be under-reported and the majority are likely to affect all species, given exposure to the related disease agents/factors.]

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