Date: Mon, 7 Jan 2013 17:37:29 -0000
From: "Martin Shough" <parcellular@btinternet.com>
Subject: Oct/Nov. 1957, United Kingdom, U=Z Cases
To: RADCAT, Fran Ridge


DATE: Oct/Nov 1954 TIME: approx. noon CLASS: R ground radar
LOCATION: SOURCES: Good ATS 1987 36, United Kingdom FSR CH 15 June 73 3 & n.p6
RADAR DURATION: unspecified
EVALUATION: No official

PRECIS: According to a War Office statement a few days after the events, radars in an undisclosed area of the UK registered "formations" of unidentified echoes on 6 occasions from late October to early November 1954. The story was covered by numerous British and European newspapers. A government spokesman quoted in the Sunday Dispatch, November 7, stated:

We cannot say what they are. They first appear in a 'U', or badly shaped hairpin, formation. After a time they converge into two parallel lines and then take up a 'Z' formation before disappearing. They are invisible to the human eye, but on the radar screen they appear as lots and lots of dots formed by between 40 and 50 echoes. They cover an area in the sky miles long and miles wide.
Every time they have been seen they followed the same pattern. It was always around midday. We have checked and found that our sets are not faulty. We are still maintaining a watch. All our sets in the area have picked them up.
The targets were first observed by a civilian radar scientist, and subsequently by all radars in the area. They always moved from E to W, always appeared at a height of 12,000' and the same regular patterns were repeated on all six occasions, whether the sky was clear or cloudy. The location was kept secret, and one operator was quoted as saying that they had received high-level orders not to disclose information. The Air Ministry, evidently keen to dampen down public speculation, pointed out that there were many possible causes of echoes on radar, such as birds, aircraft, balloons or kites. But the specialists involved did not think that such regular patterns could be explained by any of these causes.

NOTES: Immediate suspects in this case are birds or insects. Qualitatively speaking, the kind of changing linear formations described are reminiscent of the flight patterns of flocks of geese, for example. During the war so-called "ring angels" were first observed on radars near London when observers reported nothing visible to account for them. These expanding circles of echoes were always observed at dawn. They were eventually traced to the dispersal of flocks of birds from their nocturnal roosts. The flight patterns of migrating geese can be remarkably regular, tending to follow well-defined corridors, and the reported time of year is not inconsistent with this hypothesis. It is possible that different formations on successive days might exhibit a roughly similar sequence of flight patterns due to peculiarities of the local topography, or to consequent wind/convection currents. However, 12,000' is very high for geese and statistically improbable for any flocking bird over the UK, and if the operators' reports of invariably regular patterns are accurate then birds are a little improbable. It is also true that there is a marked tendency for birds to fly at higher mean altitudes in overcast as opposed to clear conditions, yet these targets were reportedly always at 12,000' irrespective of cloud cover.

Some of the larger insects can be observed on surveillance radars, though their cross-sections are very dependent on frequency and would not offer strong targets except on ultra-sensitive research radars. In this case the targets were apparently detected on "all the radars in the area". The implied volume of insects and the linear distributions might be a problem. The only candidate with an inherent tendency to long, linear distributions would be immature spiders parachuting on strands of gossamer, a phenomenon which does occur preferentially around October/November. However the backscattering cross-sections of such spiders are likely to be on the order of only 0.1 sq. cm. or less, and the number of individual arachnids required to yield detectable signals spanning an area "miles long and miles wide" is presumably untenable. Furthermore it strains credibility to imagine such structures, drifting at the mercy of winds and convection updraughts, rehearsing a similar ballet on six occasions, each at the same time of day. The same problem exists with seabreeze fronts which sometimes display as lines of scattered echoes (due in part to refractive discontinuities and in part to birds or insects lofted on the air currents) and other weather targets, such as rain or hail cells. Superrefractive anomalous propagation of ground returns is ruled out by the uncharacteristic target behaviour, apparent independence from weather conditions and the several different radars involved. Partial reflection from travelling waves on an inversion surface at about 6000' could generate linear clusters of mobile targets with apparent altitudes of about 12,000', but hardly with the same distribution on six occasions and on several different instruments.

Radio frequency interference can generate linear speckle patterns, but the displayed product of any one source of interference would be dependent on the unique bandwidth, pulse repetition frequency and scan period of the receiver among other factors. It is therefore highly improbable that "all the radars in the area", civil and military, would simultaneously display RFI signals, and virtually impossible for them all to display the same atypical patterns of blips with the same atypical cross-scope motion - not to mention concurrent detection on PPI scopes and, it is to be presumed, height-finders.

Clearly more information is needed in this case. The most probable explanation would seem to be migrating flocks of birds, but this does involve dismissing the specific assertions made by radar operators that the target formations were too regular and too accurately repeated to be due to birds.

[A curious addendum to these events is a visual report of similar phenomena over Rome on October 30 and, especially, on November 6 & 7 1954. According to Italian diplomat Alberto Perego, at that time working in Rome (he was later attached to the Italian Consulate in Belo Horizonte, Brazil) hundreds of people watched a display of numerous small lights like "white spots, sometimes with a short white trail" which formed and reformed in rough geometrical patterns resembling successively the letters 'V' and 'X', then separated into two "serpentine curves" which moved off in different directions. Perego published his descriptions in 1957. At the time he had been amazed that no newspaper reports appeared, and contacted several diplomatic colleagues and military officials about the events. No one acknowledged having any information. Interestingly, in view of the passing mention above of parachuting spiders, on both occasions Perego reports that a "shining filamentous material" descended from the sky. It "evaporated completely in a few hours." The connection - if any - between this report and the radar targets observed in Britain during the same time frame remains obscure.]

STATUS: Insufficient information