"Unintentional encapsulation in hawks has been known to occur, with decapsulation being messy and the packets mangled." Carriers being blown off course. RFC1149: "While broadcasting is not specified, storms can cause data loss." The absence of viable local carriers. RFC6214: "In some locations, such as New Zealand, a significant proportion of carriers are only able to execute short hops, and only at times when the background level of photon emission is extremely low." This describes the flightless and nocturnal nature of kiwis. Loss of availability of species, such as the extinction of the passenger pigeon. Disease affecting the carriers. RFC6214: "There is a known risk of infection by the so-called H5N1 virus." The network topologies supported for multicast communication are limited by the homing abilities of carriers. RFC6214: "... [carriers] prove to have no talent for multihoming, and in fact enter a routing loop whenever multihoming is attempted." Other avian data transfer methods Rafting photographers already use pigeons as a sneakernet to transport digital photos on flash media from the camera to the tour operator. Over a 30-mile distance, a single pigeon may be able to carry tens of gigabytes of data in around an hour, which on an average bandwidth basis compares very favorably to current ADSL standards, even when accounting for lost drives. On March 12, 2004, Yossi Vardi, Ami Ben-Bassat, and Guy Vardi sent three homing pigeons a distance of , "each carrying 20–22 tiny memory cards containing 1.3 GB, amounting in total of 4 GB of data." An effective throughput of 2.27 Mbps was achieved. The purpose of the test was to measure and confirm an improvement over RFC 2549. Since the developers used flash memory instead of paper notes as specified by RFC 2549, the experiment was widely criticized as an example in which an optimized implementation breaks an official standard. Inspired by RFC 2549, on 9 September 2009, the marketing team of The Unlimited, a regional company in South Africa, decided to host a tongue-in-cheek pigeon race between their pet pigeon Winston and local telecom company Telkom SA. The race was to send 4 gigabytes of data from Howick to Hillcrest, approximately apart. The pigeon carried a microSD card and competed against a Telkom ADSL line. Winston beat the data transfer over Telkom's ADSL line, with a total time of two hours, six minutes and 57 seconds from uploading data on the microSD card