Are our feathered friends being fooled

  hssutton 22:36 05 Jan 2017
Locked

into thinking Spring is here by the very mild winter. Today in Lincolnshire the local rookery was a hive of industry as the birds where working on their nests. Normally this happens late February.

  muddypaws 09:22 06 Jan 2017

Nothing too unusual here in DA3. Pigeons were a bit sexy yesterday! The only strange thing this winter has been the absence of squirrels. I know they hibernate, but in past winters they have been on the bird feeders quite regularly. An abundance of seagulls flying about each day (40+)and they settle on a roof a few bungalows down the road. Haven't yet discovered what the attraction is. Rooks/crows are about, but no signs of nest building. It certainly hasn't been mild here for the last week. Minus 4s and 5s most nights.

  morddwyd 09:31 06 Jan 2017

Rooks are among the earliest breeders, and display and other breeding activity is not uncommon in January. though perhaps no in Lincolnshire..

Most breeding activity, while modified by temperature, is triggered by day length.

Rooks feed a lot on leatherjackets, crane fly larvae, and a long frost free period means they are more easily accessible. Even though there may have been overnight frosts, as long as there have no been long periods where the ground has remained frozen during the day they will be able yo get through it.

Even a gtanivorous species like rooks will feed their young on more easily digestible, and richer, protein. This is the reasoning behind the popular fallacy that you should not put bird food out in the breeding season, as iy is unsuitable for nestlings.

A bird is no more likely to feed its young on unsuitable food than a human mother, and if it does it is because of faulty genetics, and it is better that any such fauly gene does not grow to breeding maturity.

  Fruit Bat /\0/\ 09:43 06 Jan 2017

Must be a bit of a micro climate in Lincolnshire

Nottinghamshire and South Yorkshire have be rather cold for the last couple of weeks

  Forum Editor 10:03 06 Jan 2017

A couple of wrens have been showing signs of next building in my garden, and robins are active.

Rooks commonly lay eggs early in March, they are very unlikely to do so before then, although nest-building may take place at any time from now on. In terms of meteorology, Spring begins on 1st March. The meteorological Spring is based on statistical temperature cycles, and that, plus extending daylight, is also what governs nesting birds.

The problem is, we are experiences warmer winters, so birds (and plants) can be fooled into starting the season earlier. The sudden onset of sub-zero temperatures will retard plant growth, and delay breeding activities in birds. Over long periods it all seems to work out - bird populations fluctuate with insect populations, apart from any other influencing factors.

The wrens and Robins in my garden are oblivious to all that. I just hope they slow down - there's not going to be much in the way of food for them for a month or so, let alone for nestlings.

  Belatucadrus 10:56 06 Jan 2017

Nothing here showing any nesting activity but this area of Worcestershire has been hit with a series of really fierce frosts and spring is most definitely not in the air.

  Forum Editor 12:41 06 Jan 2017

Belatucadrus

"Nothing here showing any nesting activity"

Spring starts in the South-West of the country, and moves North at an average speed of just under two miles an hour. It means that the north of the country sees the arrival of the first signs of Spring (ladybirds, frogspawn, leaves on Hawthorn) about three weeks after Cornwall.

One of my daughters lives near Truro, and she has forsythia in full bloom against a wall in her garden already.

On average, we are now seeing the arrival of Spring about 11 days earlier than in the 19th century.

The problem is, our climate is notoriously unpredictable on a month to month basis - we are quite likely to see substantial snow falls before this month is out.

  morddwyd 13:12 06 Jan 2017

" In terms of meteorology, Spring begins on 1st March. The meteorological Spring is based on statistical temperature cycles, and that, plus extending daylight, is also what governs nesting birds."

1st March is an entirely arbitrary date decided on by the Met Office to keep their records tidy, and to assist in the exchange of information!

Most older people have always been taught that the first day of Spring is 21 March , the Vernal Equinox (OK, so this year it's 20 March,, but you get the principle!). I can assure you that the Met Office decision does not govern nesting birds! I repeat, while temperature, and the consequent availability of food, can modify behaviour, it does not control it. That applies to most life, both plant and animal; you may see an Essex girl on the beach in March, but May is far more usual!

Some plants require a minimum of 8 hours daylight to live. The insects which live on them will not appear until the plant growth appears, and the birds which feed their young on those insects will not breed until those insects are available, it doesn't matter what the temperature is. While swallows normally follow insect hatching northwards, in the event of a cold wet and late spring they will still appear, albeit very late, and die or fail to breed, in their tens of thousands.

I cannot add much about wrens, they're not a species I know well, but many of the robins about at the moment are the Scandinavian sub-species, brighter than our own, though this is not obvious in the field. Robins are not migratory as such, but do move south for the winter. These Northern Robins are getting 8 hours of daylight at the moment, triggering their behaviour. If they were at home they would only be getting 6 hours, and they will settle down again once they go home.

Because of the similarity of day length and temperature, rooks are one of those species which will frequently show breeding behaviour in the autumn. It normally peters out after a few days, but Jourdain (1865 - 1940) actually recorded autumn breeding, though this is the only documented case I know of.

  Forum Editor 14:20 06 Jan 2017

morddwyd

"1st March is an entirely arbitrary date decided on by the Met Office to keep their records tidy, and to assist in the exchange of information!"

Nonsense. The meteorological Spring date is based on historical temperature cycle statistics- nothing to do with keeping records tidy.

"Most older people have always been taught that the first day of Spring is 21 March"

Yes, they have, but I'm not sure what your point is. I was talking about the meteorological Spring, not what older people have always been taught. As I pointed out, Spring conditions now start around 11 days earlier than in the 19th century,regardless of what people have been taught - you can't use a calendar to contradict the temperature statistics!

"I can assure you that the Met Office decision does not govern nesting birds!"

I don't know where you got the idea that I said it did. Read what I said, and you'll notice I said that birds (like plants) are affected by temperature cycles and daylight hours. Migrating and indigenous birds are hugely affected by temperature cycles, not what older people have always been taught.

"Robins are not migratory as such"

Yes, they are.

Plenty of Robins migrate here from Scandanavia, Russia, and parts of continental Europe and (usually female) robins from the UK are often found as far away as the South of Spain and parts of Portugal in the winter.

Usually, Robins in this country have found mates by the middle of January, but this year that is happening (in my garden at least) already - as I said.

I can't comment about girls (in Essex or elsewhere) on beaches in March; I bow to your greater knowledge on that topic.

  morddwyd 19:38 06 Jan 2017

"I don't know where you got the idea that I said it did."

Direct Quote

" The meteorological Spring is based on statistical temperature cycles, and that, plus extending daylight, is also what governs nesting birds.""

"and that, plus .......... , is also what governs nesting bitds.

""Robins are not migratory as such" Yes, they are."

No they are not (yes I know it is still the pantomime season!), not in the scientific or ornithological sense, any more than Curlews or Lapwings, moving down from the high moors after breeding, are migratory .

Most professionals regard their movements as simple hard weather or cold weather movements.

Migration is generally more a complete species move, at around the same time, and mostly in company. Fieldfares and Redwings are regarded as migrant thrushes, Robins aren't.

As I have pointed out before, this is an area where I am familiar with the subject, having delivered several papers and notes, some published, some not, on the subject, and having been instrumental in forcing a change of Government policy on an ornithological matter (with some support from the Duke of Edinburgh and the Audubon Society!).

  iscanut 19:49 06 Jan 2017

Our blackbird numbers have increased four fold with foreign migrants ! They are everywhere scratching up all the crocus and daff bulb heads just appearing.

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