Talk:Reverse migration (birds)

Wiki Education Foundation-supported course assignment
This article was the subject of a Wiki Education Foundation-supported course assignment, between 5 September 2018 and 28 November 2018. Further details are available on the course page. Student editor(s): Fresh oolong. Peer reviewers: Asp482.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 08:06, 17 January 2022 (UTC)

Peer Review
Hey!

A couple things I noticed with your page was the opening definition of reverse migration should be clear and concise. It may be a straight forward definition but you should still explain it, rather than saying its a phenomenon. When you're going to add more content to it for the final presentation, I suggest not focusing so much on a photo, and explain different cases on reverse migration and why birds do this.

Other than those few suggestions, it seems you're on the right track. It's organized and the photo for reference is good.

Cheers! Asp482 (talk) 18:20, 7 November 2018 (UTC)Asp

Here is what I am planning to add section by section into this article.

Edits to Reverse Migration (birds)
Reverse migration also call reverse misorientation is a phenomenon in bird migration where a bird will fly in the opposite direction during the migration time of what is species typical.

If a bird sets off in the opposite direction, shown by the orange arrow, it will end up in Western Europe instead of South East Asia. This is a mechanism that leads to birds such as Pallas's warbler turning up thousands of kilometres from where they should be. Keith Vinicombe suggested that birds from east of Lake Baikal in Siberia (circled) could not occur in western Europe because the migration routes were too north-south. Most of these lost young birds perish in unsuitable wintering grounds, but there is some evidence that a few survive, and either re-orient in successive winters, or even return to the same area.

Reverse migration is genetic or learned behaviour?
Although some large birds such as swans learn migration routes from their parents, in most small species, such as passerines, the route is genetically programmed, and young birds can innately navigate to their wintering area. Sometimes this programming goes wrong, and the young bird, in its first autumn, migrates on a route 180° from the correct route. This is shown in the diagram, where the typical migration route is shown in red but a reverse migration has occurred as seen in orange in the image.

So with some species such as swans that the migration route is learned reverse migration could occur from learning improper route from other birds.

As migration is most often genetically programmed before birth into most birds there can be rare variations and defects that change the migration programming. These variations will account for some of the reverse migrations cases but would not account for most of these reverse migrations. After these birds have changed their migration path and are surviving they will breed and reproduce some offspring with their new migration route. These offspring have not learned this new migration route for them it is genetic, and they will continue on this one and may pass it along to their offspring.

Tracking radar
A single individual is tracked using a manually operated tracking radar to understand the targets exact position and trajectory to predict where it will be. As the bird flaps their wings the echo can be recorded and compared to patterns to understand flight patterns or challenges. These were primarily used to monitor specific individuals during nocturnal migration through the night.

Radiotelemetry
This is a technique used to track animals. A miniature transmitter is attached to the subject animal and this transmitter emits a very high frequency (30-300 MHz) which can be picked up with one or more receivers. For studying the moment behaviour of birds in a migration hotspot south west of Sweden called Falsterbo near Falsterbo bird observatory three receivers were used to triangulate and track the birds.

Ringing
Ringing birds is when a light weight metal band is attach to the foot to not impair movement but stay on the bird with a identification number. This identification number can provide people catching and these birds with information such as how old they are and where they have been by examining data bases. At the Falsterbo bird observatory these birds are caught with a mist net and measured and banded.

Reverse migration is opposite direction or random directions?
Reverse migration is a widespread around the world and occurs for species migrating during the night and also during the day. This irregular migration direction is most often aproximatly opposite to what is species typical not a random direction. This phenomenon occurs not only with species finding a tropical area during the winter months but also temperate zone migrants, short irruptive food migrants, short distance migrant, and long distance migrants. An article in British Birds by James Gilroy and Alexander Lees suggests that misorientation primarily occurs approximately opposite direction but can occur in random directions. This random directions could be partly due to genetic variations or abnormalities. These birds that addopt and continue to migrate in this atypical direction have been called Pseduo-vagrancy migrators. Pseudo-vagrancy is the possibility that a bird will migrate in a different area or direction from the normal migration route. These birds migrating in a different then normal may mate and breed with other changing the gene programming of others of their species creating this new migration route for their offspring. Some species have been found to be more likely then others for having the pseudo-vagrancy migration changes. Yellow-breasted Bunting is considered a lower chance of pseudo-vagrancy behaviours as compared to the Yellow-browed Warbler for having higher chance of pseudo-vagrancy behaviours

Solitary reverse migration during the night
It was found that solitary birds migrating during the night are more likely to reverse migrate West when East is the regular migratory path. This West to East reverse migration was seen observed more often than a reverse migration to the North rather than the normal South migration. To only examine single species this study examined birds solitarily migrating during the night so that they do not group-migrate and influence other species to follow or follow other species.

Reverse migration due to inadequate fat stores
Reverse migration is more likely to occur with bird species that have low fat storage compared to higher fat storage. Using radio tracking thrush songbirds migrating southwards were tracked to examine when and why some during a stopover along the northern coast of Mexico some would not continue south but fly inland northerly. These songbirds that changed their normal seasonal southerly migration were almost all found to be lean and low on fat stores. This inland northerly path may show that the normal stopover location did not have adequate resources to increase fat stores of these birds, because they were unable to gain enough fat stores these reverse migrating songbirds moved inland northerly in search of more food.

The reverse migration behaviour has also been seen in shorebirds red knots who fly in the reverse to typical migration direction. These red knot birds that demonstrated travel 200km reverse migration behaviour have been documented over the last 10 years and is a common occurrence. In this study there was not significant difference in body mass fat stores or sex for these reverse migrating birds. It was seen that the birds that made the reverse migration had significantly lower hematocrit which is the percentage of red blood cells. It has been examined before that birds increase their hematocrit before consuming large amounts for fat stores in order to have energy for their long migration flight. This would explain why these birds were choosing to travel in reverse 200km for high quality soft shell prey to supply fat and increase their hematocrit blood levels before attempting the long migration flight.

Thanks, Fresh oolong (talk) 16:38, 18 November 2018 (UTC)

Wiki Education assignment: Field Ecology and Conservation Technology
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